2000.07

In this paper, the stability criterion for cryocoolercooled hightemperature superconducting (HTS) coils is discussed. We choose the current, Itr at which "thermal runaway" occurs, as a stability criterion and adopt the relationship between the cooling power of GM cryocooler and the heat generation in coil system to evaluate Itr. We also investigate the transient behavior during a quench process in HTS coils by a newly developed FEM computer program.

The analysis of current distribution in a solidly modeled coil is very important for accurate analysis of electric machines such as deflection yoke(DY). In general, Modeling every coils is impossible for analyzing magnetic field using the 3D FEM, so solidly modeled coil is usually used. Some methods have been developed for analyzing current distribution, but these methods have fatal disadvantage that they cannot be applied to an arbitrary shaped coil and that they yield numerical errors. In this paper. a novel method for resolving the problems mentioned above is proposed. The new method is verified by the application to a DY and it shows improved results.

Induction Heating is utilized in a large and everincreasing number of application. The most prominent of these are billet heating, heating treating. metal melting. In this paper, we are modeling of the inductor and calculating of the circuit parameters is described. Analyzed by finite element method and then Inductor's characteristic analysis was studied and perform the test of temperature distribution.

Ko, RockKil;Bae, JoonHan;Sim, KiDeok;Jin, HongBeam;Lee, EonYong;Kwon, YoungKil;Ryu, KangSik 597
Fabrication of superconducting magnet system needs highdegree technical knowhow, which require not only a lot of investment of manpower and finance but also that of long time. Until now, we have met many technical problems and it have been solved by trial and error. In fact, we have got chance to come into contact with researches into the magnet design for MRI easily but did not contact with the process of fabrication and the techniques. We introduced process of fabrication and techniques for MRI magnet system until before the superconducting magnet combine with cryostat in Korea Electrotechnology Research Institute. 
This paper deals with finite element analysis of 2GVA superconducting generator which has slitted electrothermal shield in daxis. Open emf voltage is calculated and three phase fault is considered to Predict the generator parameters by F.E.M. Results show that quick response excitation could be applied to superconducting generator with slitted electrothermal shield.

Bi2223 테이프는 송전케이블과 같은 저 자장 전력시스템의 응용에 가장 유망한 선재로 알려져 있다. 송전케이블에 교류 전류가 인가되면 인접한 테이프에 의해서 발생되는 자계는 통전손실에 영향을 미치게 된다. 이와 같은 실제 송전케이블의 응용 측면을 고려하여 좌측 및 상부인접전류가 통전손실에 미치는 영향에 대하여 조사하였다. Bi2223 테이프의 통전손실은 교류 인접전류가 증가함에 따라서 급격하게 증가하는 반면, 직류 인접전류의 영향은 무시 가능한 정도로 작았으며, 인접전류가 큰 경우는 테이프의 배열에 무관한 반면 작은 경우에는 상부배열인 경우의 영향이 큼을 알 수 있었다. 또한 Bi2223 테이프의 통전손실은 교류 인접전류의 주파수에 무관함을 알 수 있었다.

Although Equvalent Magnetic Circuit (EMC) method. Using lumped parameter and numerical analysis method are widely used for electric machine analysis. these are neither always accurate enough nor sometimes available to easily use. Moreover three dimensional finite element method (3DFEM) is inherently unsuitable for electric machine performance evaluation due to its poor computational efficiency, such as too long calculation time and difficulty in modeling for analysis. In this paper, Nonlinear Equivalent Magnetic Circuit (NEMC) method in combination with 2DFEM is proposed to analyze the electric machine requiring 3DFEM, and this method applys to torque evaluation for rotary actuator of Electro Magnetic Electronic Controller Power Steering (EMECPS).

The static characteristic of a piezoelectric beam is for finding resonance frequency of the beam. In practice, it is required to analyze the beam with external command circuit including capacitors, inductors, and resistors for control. It means that the proper analysis of a piezoelectric beam with external command circuit is required by a dynamic analysis. We can also got transient and steadystate solution from the analysis. In this paper, the static and dynamic characteristic of the piezoelectric beam using FEM(Finite Element Method) are proposed.

Rotor eccentricity exists extensively in BLDC motors because of manufacturing imprecision or bearing defects. In this paper, magnetic fields of a BLDC motor with static rotor eccentricity are analyzed by the time stepping finite element method. Torque ripple, cogging torque, winding current, counterem! and unbalanced magnetic force characteristics are obtained. These results are compared with those of a noneccentric BLDC motor.

A ferrite bonded magnet type brushless DC (BLDC) motor which do not have rotor core is analyzed by using finite element method (FEM). The magnetization distribution of the magnet does not have only parallel or radial direction. So, the direction and intensity are taken into account by the analysis of the magnetization procedure. The validity of the analysis method is verified by comparing the analyzed results with measured ones.

This paper deals with the mechanical stress analysis caused by the electromagnetic radial force and the design considering the stress. The link in an Interior Permanent Magnet Brushless Motor(IPM) have influence on the mechanical and magnetic performance. Therefore, it is necessary to determine the appropriate link thickness. The optimal geometry link is designed by using the coupled with structural and electromagnetic Finite Element Method.

Linear pulse motor have many advantages. (simple control circuit, high stiffness characteristics, etc.) So, it may replace the solenoid as the valve driving device without difficulty and give full play to control the valve accurately. In this paper, we will analyze the LPM for designed proportional control valve and will conform the complex magnetic circuits to be composed LF and TF path.

For the finite element analysis of highly saturated rotating machines involving rotation of a rotor such as dynamic analysis. cogging torque analysis and etc, so much time is needed because a new system matrix equation should be solved for each iteration and time step. It is proved in this paper that. in linear systems. the computational time can be greatly reduced by using the domain decomposition method (DDM). In nonlinear systems. however. this advantage vanishes because the stiffness matrix changes at each iteration especially when using the NewtonRaphson (NR) method. The transmission line modeling (TLM) method resolves this problem because in TLM method the stiffness matrix does not change throughout the entire analysis. In this paper, a new technique for FEA of rotating machines including rotation of rotor and nonlinearity is proposed. This method is applied to a test problem. and compared with the conventional method.

This paper treats the dynamic analysis and test results of Linear Induction Motor. The dynamic analysis is performed by the d,q axis equivalentcircuit model. Equivalentcircut parameters are obtained with noload, lock test and field analysis. As a results, simulation results are compared with that of dynamic test.

This paper deals with the design of a inner rotor type Brushless DC (BLDC) motor for Electric Power Steering to reduce the cogging torque. The effect of the design parameters on the characteristic and cogging torque is analyzed by Finite Element Method (FEM). The considered design parameters are as follows : the number of pole and slot. deadzone and skew angle. and teeth shape. The winding resistance of each motor is calculated and the characteristic curve is derived from considering reactance drop voltage for original model.

This paper presents a simple analysis method for inverterfed induction motor using F.S.M and equivalent circuit. This analysis is carried out to analyze an induction motor driven by the sinusoidal voltage and the inverter. The results are verified by comparing with those of the timestep F.E.A and the experiment.

To analyze the transient state of an induction motor, there have been studies for using the magnetic equivalent circuit method (MECM) instead of the time differential finiteelement method, MECM which analyzes magnetic equivalent circuits after converting each part of an electric machine into the magnetic circuit elements. has the merits of short calculationtime and comparatively accurate results. To analyze an electric machine with MECM, we have to replace stator and rotor with the magnetic elements and express the air gap, where electromechanical energy conversion takes place, with the permeance. So in this paper, to analyze an Induction Motor with MECM, we express the magnetic equivalent circuit as algebraic equations and then as the matrix for solving easily them.

The main source of vibration in SRM drive is generated by rapid change of radial force when phase current is extinguished by commutation action. In this paper a hybrid excitation method is proposed to reduce vibration and acoustic noise of SRM. The hybrid excitation has 2phase excitation by long dwell angle as well as conventional 1phase excitation. The vibration and acoustic noise are reduced because the scheme reduces abrupt change of excitation level by distributed and balanced excitation.

Because of high torque and easiness of speed control, Direct Current(DC) motors are used long time. But, its applications are limited in circumstance and performance, since they contained brush and commutator. The commutation characteristic gives effect to life and performance of DC motor. Naturally, the commutation characteristic analysis is strongly required. In this paper, With the result of finite element analysis. The inductance is calculated each rotor position and applied to the voltage equations coupled with commutation equation. The time derivative term in the differential equation is solved in time difference method. This algorithm was applied to 2pole shunt DC motor. We considered commutation characteristic by changing contact resistance between brush and commutator segment.

An induction motor can be controlled like a separately excited do motor by field oriented control(or vector control). In vector control, Because the transformation of the stator's 3phase current into two orthogonal current is required. the control scheme is complicated. But, Yamamura proposed a field acceleration method(FAM) without the phase transformation. FAM simplify an implementation control scheme for induction motors. In this paper, the analysis of transient phenomena of a squirrelcage induction motor was achieved by the spiral vector method and the phase segregation method. It simplified control schemes more than those of vector control.

This paper presents a optimization procedure by using Response Surface Methodology(RSM) to determine design Parameters for reducing cogging torque in BLDC motor of Electric Power Steering (EPS). RSM is achieved through using the experiment design method in combination with Finite Element Method and well adapted to make analytical model for a complex problem considering a lot of interaction of these parameters. Moreover, Sequential Quadratic Problem (SQP) method is used to solve the resulting of constrained nonlinear optimization problem.

Proposed slotless PM machine is constructed without stator winding slots. Its stator magnetic material is in the form of a ring and winding have a toroidal configuration and its rotor consists of a 4pole Halbach array or radially magnetized PM rotor. Thus, airgap flux density distribution and induced emf waveform are essentially sinusoidal. Open circuit magnetic fields and developed torque of each type are presented from the analytical method and finite element method.

A movingcoiltype linear oscillatory actuator(LOA) consists of the NdFeB permanent magnets with high specific energy as the stator. a coilwrapped nonmagnetic hollow rectangular structure. LOA system have the push/pull effect caused by the unbalanced magnetic field. In order to eliminate the unbalanced thrust, we propose the control algorithm and construct the LOA driver. As a results, we obtain the balanced oscillating thrust.

Recently, the skeleton type 2phase brushless DC motor has been used in electric home appliance for low price and low energy consumption. In this paper, we analyzed a skeleton type 2phase BLDC motor using timestep finite element method. And the validity of analysis is confirmed by measuring the flux distribution on the surface of permanent magnet and backEMF. As well, we have calculated the dynamic characteristics of target motor considering the Hall sensor position. So, we have found the optimum switching position, and improved efficiency of 2phase BLDC motor.

It is demonstrated that the torque performance of the flux barrier type synchronous reluctance motor(SynRM) can be improved in terms of geometric parameters. Torque ana power factor are related to the difference of inductances and the saliency ratio. And these inductance characteristics are determined by the geometric parameters of rotor: the number of layers. the width of iron to the width of flux barrier(
$K_w$ ). slot number and shape, airgap, bridge, etc. The relationship between geometric parameters. especially,$K_w$ and motor performance will be studied. This paper shows that torque and power factor are improved through redesign with considering geometric parameters. Performance comparisons of proto type SynRM and improved SynRM are given by FEA(Finite Element Analysis). 
We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on 2inch diameter saphire substrates Two SFCLs with nearly identical properties were connected in series to investigate the simultaneous quench. There was a slight difference in the rate of voltage increase between two SFCL units when they were operated independently. This difference. however, resulted in significantly unbalanced power dissipation between the units. This imbalance was removed by connecting a shunt resistor to an SFCL in parallel. The appropriate values of the shunt resistances were
$80{\Omega}$ at$75 V_{rms}$ .$100{\Omega}$ at$100 V_{rms}$ and$110{\Omega}$ at$120 V_{rms}$ , respectively. Increased power input at high voltages also reduced the initial imbalance in power dissipation. but with increase in film temperature to higher than 200 K. 
The LIMs performance online monitoring system is proposed by using LabVIEW software and A/D board. The online monitoring system setup can measure input voltage. current, power, power factor, electromagnetic thrust, and efficiency etc. This paper reports data on LIM performance measured by the proposed online monitoring system.

This paper introduced the scheme that it improved performance of magnetic levitation system with zero power controller. Magnetic levitation is used widely, but it is complicated and difficult to control due to having nonlinear characteristics of gap and current. So, it is proposed a scheme considered changed gap according to variable load and is verified by simulation and experiments in this paper.

The paper presents design procedure and characteristics of Switched Reluctance Motor(SRM). SRM is capable of application to various field because of its constructional advantages. In design procedures, pole shoe will be considered. First step, overall design will be accomplished using PCSRD. Then, inductance and torque characteristics is inspected with motor geometries by FEA.

In the paper the eddy current loss in brushless DC motor due to switching frequency supplied by PWM inverter, is analyzed. The compensated conductivity is used in order to analyze the eddy current loss in brushless DC motor which has lamination structure. The eddy current loss is deceased when switching frequency supplied by PWM inverter is gradually increased from 1.2kHz up to 12kHz. The high switching frequency of PWM inverter make the output wave into a similar sine wave and this leads to the decreasing eddy current loss.

Kim, JunHo;Lee, EunWoong;Oh, YoungWoong;Kim, SungJong;Woo, SungBong;Lee, MinMyung;Lee, JongHan 678
We designed and manufactured DSPSRM using the usual output power equation of rotating machine. And the sinusoidaly approximated torque characteristics are achieved by 3D finite element analysis. Also, We calculated average torque per rotation using approximated torque data, calculated by 3D finite element analysis. On this paper, We manufacture torquemeter set and measure the torque characteristic of DSPSRM. 
This paper presents to find suitable driving voltage source for movingcoiltype linear oscillatory actuator(LOA). Thus, we construct control system and proposed three type driving voltage source. This scheme demonstrated experiments. Then, we find suitable driving voltage source for LOA.

Switched reluctance motor(SRM) has the advantages of simple structure, low rotor inertia. and high efficiency. However position sensor is essential in SRM in order to synchronize the phase excitation to the rotor position. The position sensors increase the cost of drive system and tend to reduce system reliability. This paper investigates the speed control of sensorless SRM in which the phase current and change rate are utilized in position decision, and the period of dwell angle is variable by compensating the rotor angle for speed control. The proposed system consists of position decision. phase locked loop controller, switching angle controller and inverter. The performances in the proposed system are verified through the experiment.

Molten Carbonate Fuel Cell (MCFC) with high electrical efficiency and low environmental effect has been developed for the commercial application of power generation fields. Recently we have built a 25 kW molten carbonate fuel cell power generation system and tested it. The MCFC system is composed of diverse peripheral units such as reformer, preheater, water purifier. electrical loader, gas supplier, and recycling systems. The stack itself was made of 40 cells of
$6.000 cm^2$ area each. The stack showed an output of 28.6 kW power and a reliable performance at atmospheric operation. while in pressurized operation the stack showed an output 25.6 kW lower than the atmospheric operation. The reason of lower performance of pressurized operation was caused from a gas cross over shown in few cells in the stack. 
In this paper voltage distribution in the windings of an inverter fed induction motor is studied. High frequency parameters of the induction motor are calculated using finite element analysis. With these parameters. a high frequency equivalent circuit of the invertercablemotor is formed. The transient analysis is performed using ATPEMTP package to estimate the voltage distribution in the motor windings.

Wide operating range and speed control is needed for wind power generating and a Doubly Fed Induction Generator(DFIG) has good adaptivity for that purpose. This paper deals with power and power factor control using the Grid connected DFIG in the wide speed regions, by controlling frequency and voltage fed to the rotor. Power flow of the DFIG and steadystate algebraic equations of the equivalent circuit are analyzed. For a normal operating region, in which the generator ratings were not exceeded, the rotor current was either less than or equal to the rated value. Accordingly, the optimal power factor can be selected relative to the permissible rated current at the rotor coil which controls the magnitude of the injected rotor voltage to the rotor according to a given rotor frequency.

A new high voltage generator is designed and basic performance analysis by 2DFEA is performed. The new generator is able to supply electricity directly to the high voltage grid without the need for a stepup transformer. For the 2DFEA analysis, the generator model is coupled to external circuit components with inductance and endwinding resistance.

It leaves much room for improvement that UTM01 is of practical use. Therefor we will design of UTM02 system. The design of new magnet is based on light weight for bogie system. We used Maxwell3D FEM for design of new magnet. The new magnet for UTM02 that was reduced weight of magnet. 22kg, then it was increased ratio lift to weight is 9.87.

Designing of the squirrel cage AC Traction Motor has many difficulties which has to be small shape in order to be suitable into bogie frame, high efficiency and light weight. It means that induction motor for tractive efforts has to be different magnetic and electric loading ratio from industrial induction motor. This paper is devoted to an examination of how this ratio affects overall design concept and. hence the main design points for traction motor. Also studied is the changed coefficients of the magnetic and electric loading ratio squirrel cage induction motor for the traction purpose, which has been already identified from the referance book for industrial purpose induction motor.

In this paper, a static synchronous compensator(STATCOM) is proposed in order to compensate both negativesequence and reactive power. The STATCOM control unit is designed considering the proposed compensation scheme for the unbalanced loads. As a result, the effectiveness of the STATCOM for compensating both negativesequence and reactive power is verified by computer simulations.

The interaction of electromagnetic forces and mechanical structure of switched reluctance motors(SRM) is the major cause of the noise and vibration. The stator part in SRM produces the most vibrations. Therefore, it is necessary to know the natural frequencies of the stator. In this paper, the variation of natural frequencies according to the design parameters is investigated to avoid the resonance. The natural frequency of the tested motor is founded by the frequency response function obtained by a experimental modal analysis.

Recently, the insulation breakdown accident happened at 6.6kV inverter driving motor brings out the reliability decrease to the motor driving system. We need to find the solution with system engineering level. The objectives of this study are developing the appropriate filter for the drive to protect the motor and the insulation system of motor which is driven by inverter. The circuit parameters of cable are calculated by EMTP(Electromagnetic Transient Program) to simulate the system. And we use MATLAB to find the appropriate filter parameter. The simulation and the test results are compared to verify the suitability of the filter parameter. We clarify the cause of the deterioration of the inverter driving motor through the analysis of insulation breakdown accidents. The endurance test scheme and the configuration method of insulation system are established.

In the Systemintegrated modular advanced reactor(SMART), the motor for Control element drive mechanism(CEDM) requires high density power and simple drive mechanism to reduce volume because of restriction by installspace and must satisfy the reactor operating circumstances with high pressure and temperature. In this paper, we perform the basic design of the two kinds (Variable reluctance type and Hibridreluctance type) of the transverse flux motor to develop the prototype motor for the control element drive mechanism of SMART. Analyzed these motors by the FEM in the 2dimension, we show the characteristics for each of the analysis model.

In this paper, we discussed an optimal design of BLDC motor using rare earth magnet. In motor design using rare earth magnet, because of the characteristics that rare earth magnets have high remanence, the effect of saturation of steel has to be considered. For this, we used nonlinear finite clement method. For optimal design, a Niching genetic algorithm is used. As a result, we found out a set of BLDC motor shapes increasing motor efficiency, and decreasing cogging torque.

Single phase series commutator motors is widely used in various home appliances, such as vacuum cleaner, electric mixers, electrical tools, etc. This paper deals with the characteristics of single phase series commutator motors of which parameters varied with stator turns and stack length to find optimal electric and magnetic loading. We try to measure these data through the experiments with several prototype motors. The experimental results show some specific stator turns and stack length with which this motor has the highest efficiency.

This paper presents a parameter identification method to estimate the stator resistance. stator inductance, rotor resistance and rotor inductance of the induction motor. A step voltage is applied across the stator terminals while the machine is in the standstill condition, and the resulting stator voltage and current response are measured. Observer/Kalman Filter Identification(OKID) algorithm is used to estimate induction motor parameters. Simulation results are presented to verify the identified model.

In this paper, after considering the standard data that are obtained by the study of the dynamic and mechanical characteristics (such as the torque characteristics and the force distribution analysis of the wobble motor), we design the prototype of the magnetostatic wobble motor. It can be applied to the highprecision medical instruments such as the ultrasonic catheter for the diagnosis and treatment of vascular disease.

This paper presents a simple method for determining the minimum value of capacitance required for initiating self excitation in threephase selfexcited induction generator. Based on the steadystate equivalent circuit model, this paper presents simple and direct method to find the minimum capacitance requirement under RL load. Using the loop impedance and nodal admittance. the minimum capacitance is determined by self excitation condition. These computed values can be used to predict practically the minimum value of the terminal voltage required for selfexcitation. To maintain a constant terminal voltage, a method for determining the frequency, terminal capacitance, and exciting reactance is also described.

An 1.2[kw] SRM for a pallet truck drive is developed and tested. The drive system has to operate with low voltage and high current. and has to have the characteristics of DC series motor. The small size, ruggedness, high efficiency make it possible to replace with DC motor. Test results show that pallet truck with SRM has better characteristics than that of the DC motor performance.

An axialflux permanentmagnet machine(AFPM) topology with coreless winding is proposed. In the proposed AFPM configuration. the winding consists of a hexagonshaped coils encapsulated in fiberreinforced epoxy resin. Due to the lack of the iron core. the overall machine structure has high compactness and lightness. The simplified design calculation of the back emf was obtained. In this study, motor design was carried out using the software package Maxwell. This paper discusses the basic design of coil winding of AFPM motor. Experimental results were taken form a prototype machine rated 0.4 Nm, 2000 rpm.

This paper presents the design process for series wound DC motor with the brush by using the experimental data of a tested motor. The design parameters calculated from the experimental data are friction loss. windage loss and contact resistance of brushes. The characteristic analysis of the designed motor is performed and then the proposed method is verified by comparing with experimental result.

In this paper the relationship between the pressing force applied to rotors and the characteristics of ultrasonic motor are discussed. The characteristics of ultrasonic motor using a piezoelectric vibrator were systematically studied. And these were applied to the construction of a card forwarding device. The principle of ultrasonic motor is to use an elliptical motion generated on the side of the vibrator, and the elliptical motion of the ultrasonic motor was obtained by complex oscillation of
$L_1B_4$ mode. As the experimental results. the forwarding speed of the card increased linearly as the pressing force applied to rotors increased. The forwarding speed of the card was 16.0 cm/s when the pressing force applied to rotors was 1 N. The forwarding force of the card increased linearly as the pressing force applied to rotors increased. The forwarding force of the card was 398 mN when the pressing force applied to rotors was 1 N. Therefore, this ultrasonic motor can be expected to be used for cardforwarding device and so on. 
This paper presents an optimum design of a linear induction motor(LIM) using genetic algorithm(GA). Sequential unconstrained minimization technique(SUMT) is used to transform the nonlinear optimization with constraints to a simple unconstrained problem. The objective functions of LIM such as trust, weight are optimized and the result was applied to the design of linear induction pump.

This study deals with the characteristic analysis of slotless PMLSM based on the analytical method. Slotless PMLSM produces the thrust ripples due to the harmonic component of backEMF. Therefore, this paper presents the thrust ripple minimization technique, by modifying the pole ratio and the coil width. The results of the proposed mehtod are compared the ones of FEM.

ADD is under development for the high speed motor. This paper describes simulation and test results for obtaining the maximum output by leading angle of encoder. So we carried out the test for obtaining the optimum leading angle of encoder. Maximum output 80[kW] at 20,000[rpm] was obtained at leading angle of encoder at near
$22^{\circ}$ . We confirmed the maximum output 106[kW] of 25,000[rpm] at leading angle of encoder at$34.6^{\circ}$ . 
In this paper, the IPD control algorithm using the coefficient diagram method(CDM) controller design of the Linear DC Motor(LDM) is presented. Recently LDM has been used to obtain the fine results of the dynamic characteristic for straightly moving condition. The IPD control algorithm has a robust response to force disturbance. The effectiveness of IPD is shown by simulations and comparison with PID.

The problem in improving the positioning precision of a permanent magnet linear synchronous motor(PMLSM) is the large detent force caused by the permanent magnet. The detent force is thought to arise from the difference of the position of a permanent magnet end and a tooth position. In this paper, Three methods of reducing detent force is presented The first method is adjusting the width of permanent magnet. The second method is varying the shape of armature teeth. The third method is the arrangement of the permanent magnet end. This paper compares with the ratio of reducing the detent force according to the three methods.

Hybrid type LPM can be widely applied in the precise position controlled devic because precise linear motion can be directly obtained by the simple control circuit without backlash in the rotarytype stepping motor. Also, LPM can increase the Position resolution, which was limited by mechanical manufacturing limit and characteristic of magnetic material. using microstep drive method to decrease the noise and vibration further. Especially, Doubleside LPM may be replaced the solenoid as the valve driving device without difficulty and give full play to control the valve accurately. Hence, In this paper, magnetic circuit of doubleside LPM was confirmed and static thrust force curve according to the relative displacement between stator and mover, was analyzed by the two dimensional finite element method. From this results, we can suppose the excitation current to be controlled optimally.

Detent force is produced in a permanent magnet linear machine. It is generally an undesired effect that contributes to the output ripple of machine, vibration and noise. This paper analyzes detent force in a Permanent Magnet Linear Synchronous Motor (PMLSM) by using various detent force minimization techniques. A twodimensional Finite Element Method(FEM) is used to predict detent forces due to structural factors and nonlinearity. And moving node technique for the drawing models is used to reduce modeling time and efforts.

In this paper, we present the optial design and analysis of a novel brushless do linear motor, which can operate as a selfless linear stepping motor, with two armature cores and two back iron and five high energy product magnets. We used Maxwell program package for computing the flux distribution and static force. The assessment of the analytical and measured values shows a very goof correlation among them. The result are presented in this paper.

저 주파수에서 인덕턴스를 정밀하게 측정하는 방법은 RLC를 이용한 resonance 방법과 교류브리지를 이용한 방법이 있다. 현재 선진 국가표준기관에서의 인덕턴스 표준유지는 약 5 ppm정도이고, 인덕턴스 측정브리지는 국가에 따라 자체 개발하여 사용하며 평균적으로 약 20 ppm의 불확도로 보급을 하고 있다. 이러한 세계적 수준으로 인덕턴스 표준을 유지, 보급하기 위하여 10nF의 전기용량 표준으로부터 10 mH의 인덕턴스를 유도할 수 있는 Maxwellwein bridge가 개발이 되었다. 이 브리지가 개발됨으로서 10 mH의 경우 400 Hz
$\sim$ 5 kHz의 주파수 범위내에서 약 8 ppm($2{\sigma}$ )의 불화도로서 인덕턴스 표준을 유지할 수가 있게 되었다. 
The objective of a cathodic protection system (CP) is to protect the buried metallic structure against the corrosion caused by chemical reaction between the buried structure and the surrounding medium, such as soil. This paper presents a boundary element application to determine the optimal impressed current densities in a cathodic protection system. The potential within the electrolyte is described by the Laplace's equation with nonlinear boundary conditions which are enforced based on experimentally determined electrochemical polarization curves. The optimal impressed current densities are determined in order to minimize the power supply for protection. The solution is obtained by using the conjugate gradient method in which the governing equations and the protecting conditions are taken into account by the penalty function method. Numerical example are presented to demonstrate the practical applicability of the proposed method.

Superconducting racetrack coils are used in areas of generators, motors, wiggler magnets and so on. Especially now a days many advanced nations including U.S., Japan are developing high temperature superconducting(HTS) wire which has better performance than low temperature superconducting(LTS) wire. Most of HTS wires such as Bi2223 are manufactured with PIT(Power In Tube Method) process, so the shape of the wire looks like tape different from LTS wire of round shape as normal conductors. Generally HTS racetrack coils are composed of a few partial doublepancake colis and then the doublepancakes are jointed each other according to their applications.

Due to the long time operation of the thermal power plant boiler. the load redistribution of the sling rods is occurred. To enlarge the sincerity of the boiler. measuring and adjusting the actual load of the sung rods is required. The original targets were reached from the 1yearstudy. Survey related to the load distribution system for the boiler, systematic design of the hydraulic unit and hydro cylinder, detailed design of the hydraulic unit and hydro cylinder.

In developing the assemble HEPA(High Efficiency Particulate Air) Filter, the main frame and sub frame can be easily assembled and disassembled and tightly sealed. The sub frame(included Media) will be made of the manageable material. so it will be easily compacted with the spent filter compactor. It does not take a lot of time for disassembling the spent filter. The main frame can be recycled and the volume of the spent filter is reduced, so the cost for treating the radioactive waste is reduce. And the changing costs can be reduced, because the cost of the media is lower than the filter.

최근에 주목받고 있는 초고속 구동 전기기기의 전자기 설계에 있어서는 일반적 설계법외에 고려하여야 할 상수들이 있다. 10만 rpm급의 고속회전이 필요한 전자기 응용기기들은 물리적 접속이 불가능하며, 초고속 switching이 가능한 전력소자나 높은 주파수에서도 eddy current 및 hysterisis loss를 최소화 할 수 있는 강판 제질의 개발이 선행되어야 가능하다. 본 논문에서는 이러한 초고속 구동을 하는 전자기 응용 기기의 설계에 있어서 고려하여야 하는 유기 기전력, 풍손, 마찰손, eddy current and hysterisis loss 와 같은 철손 그리고 toothripple losse 등에 대한 연구결과를 설명하며, 초고속 전자기 응용기기의 구동 특성과 초고속 회전에서 가장 우려되는 고주파 손실을 최소화하고 고효율을 유지하기 위한 최적형상 설계를 제시한다.

This paper describes the theory and practical design of Rogowski coil and active integrator. The coils and integrators have the ratings as follows. 1) current ratings between 20kArms and 200kArms 2) current duration 3 seconds 3) time constant of primary circuit looms 4) inner diameter of coil is suitable for mounting at the busbar
$200mm{\times}200mm$ . The actual results in the shortcircuit tests and compare with other sensors, such that shunt. are given also. 
This paper describes the design and the analysis of electromagnetic system of Magnetic Switch using 2D parametric finite element method(EMPulse). Magnetic Switch is electrical equipment, which is widely used for switching on/off motors in industrial field. The transient state is simulated in order to calculate the response time of Magnetic Switch. The simulation is based upon a stepbystep integration of the electric circuit equations and the core movement. The contactor uses a permanent magnet for maintaining the closed state. The presented solution takes account of nonlinear magnetic material property and spring force controlled by core position. The dynamic response of Magnetic Switch predicted by the simulation agrees closely with the required condition.

The analysis model of voltagesag compensator is achieved in synchronous rotating coordinates. Inverter's LC filter and DClink capacitor is designed in order to reduce THD of output voltages and LC filter's size And the circuit parameters of voltagesag compensator is presented for 3phase Customer.

전기기기의 구조 및 형상 최적화에 있어서 다양한 제한 사항과 설계방법들을 이용하기 위하여 전역 최대점과 함께 국소 최대점까지 고려할 수 있는 최적화 기법이 요구되고 있다. 다양한 제한사항들을 모두 목적 함수에 포함시킬 경우에 발생하는 여러 가지 문제점들을 해결하고 설계자의 주관적 평가도 활용할 수 있는 새로운 기법을 필요로 한다. 이처럼 다양한 해의 생성과 보존을 필요로 하는 분야에 니체(niche) 개념이 이용될 수 있다. 본 논문에서는 니체 개념을 포함하는 유전 알고리즘을 이용하여 토크의 선형성을 보장하는 토크 모터의 최적 설계를 수행하였다. 최적 설계 결과를 전역 최대점만을 찾는 최적화 기법과 비교하여 그 타당성을 입증하였다.

The large scale magnets like thermalnuclear fusion devices are necessary for superconducting CICC cable, When the Cable In Conduit Conductors(CICC) is occurred by the external turbulence, the CICC occurs to quench, The CICC can be broken because the CICC spends all energy in the quenchhappened spot. Therefore, it is necessary to develop measurement systems of the quench detection. The measurement systems of the relative good degree of efficiency are the voltage tap sensors. The weak points of voltage tap sensors are effected by EMF noise and inductance. The thermalnuclear fusion devices easily can't measure inductance value because of plasma current. In the experiment, The value of inductance was estimated by FEM techniques and the decrement of Inductance value measured as long as remaining plasma current.

동일한 임계전류 특성을 갖는 Bi2223 테이프에 전력기기의 실제 응용에서 발생되는 큰 사고전류를 고려한 임계전류보다 큰 과임계전류를 흘렸을 때 테이프의 온도상승 및 저항 특성을 중요한 인자에 대해 조사하였다. 냉각이 좋은 즉 비절연 테이프의 경우 온도상승은 없고, 표피효과에 의한 저항의 증가도 없고, 특히 비절연 테이프의 경우 과도 및 정상 상태 저항이 동일한 반면 절연 테이프의 경우 매우 상이하고, 전기절연 길이를 전압탭보다 길게만 해주면 길이에 무관하게 온도상승 및 저항이 동일하였으며 마지막으로 모재의 저항율이 상이하여도 임계전류만 동일하면 온도상승 및 저항은 유사함을 알 수 있었다.

We are developing a smallsized superconducting magnetic energy storage (
$\mu$ SMES) magnet with the storage capacity of a few megajoules, which provides electric power with high quality to sensitive electric loads. As the earlier step of the fabrication of the$\mu$ SMES magnet, this paper describes recovery current experimental results of a kA class superconductor. Recovery current of a superconductor was tested in two points of copper ratio and cooling effect. 
Superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire as transformer. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we calculate inductance and current distribution for 4layer cable using the electric circuit model and compare calculation results of transport current losses by monoblock model and Norris equation

This paper is concerned with the development of PC based computer simulation and design tools for autoexpansion SF6 circuit breaker with the arc rotary. The simulation model takes into account radiation transport, turbulence enhanced momentum. energy transport. The conversation gas dynamic equation together with Maxwells equations are solved. For the arc simulation the straightforward procedure has been used. The temperature, gas density and velocity space distributions within the circuit breaker are simulated in details. The presented results show that the computer simulation of gas flow in SF6 interrupter is a subject of much interest for design and optimization of contacts. The presented results show that the shape and sizes of contacts are chosen by this tool from judiciously compromise between electrical breakdown strength and interruption ability that are functions of gas flow parameters.

본 논문에서는
$SF_6$ 차단기 내의 대전류 아크에 대한 수치적인 해석을 모의하는 도구를 제시한다. 대전류의 차단을 위해서 해석을 통해 열적 파괴를 예측하는 것이 필수적이다. 본 논문에서 사용한 방법은 FVFLIC(finite volume fluid in cells)이며 지배방정식은 압축성 오일러 방정식으로 아크와 유동의 상호 작용을 해석한다. 아크는 기본적으로 에너지 보존식에서 열소스항으로 나타나며 주울열과 복사항으로 표현된다. 주울열은 플라즈마 영역내의 전계해석을 통해 계산되며 복사항은 방출과 흡수항의 합으로 나타내어지고 이것은 국소적인 온도와 압력의 함수이다. 본 논문에서는 수정된 방출과 흡수 모델로 복사 열전달을 계산하였다. 
The purpose of swing analysis for prefabricated jumper devices are to prevent flashover between jumper device and tower post. To prevent flashover. proper weight is add to the horizontal rod. This paper is a proposed to the analysis methods and the effects for unbalanced swing characteristics of prefabricated jumper devices. And the proposed technique is applied with the 345kV and 765kV transmission lines.

To apply HTS to AC devices, it is necessary that study theoretically and experimentally to analyze the AC losses. It should be investigated the theoretical mechanisms precede the actual experiments. Because the AC losses cause some complicated troubles in AC machines, we can design the machines properly. In this study, firstly we analyze the basic cause of AC losses by investigating the several loss factors, secondly measure the AC losses of HTS by using Magnetization. Technique and this results show that AC losses of HTS is tenuous than those of general materials used in power system. Consequently we can compare the actual results with the theoretical results. And we find that AC losses of HTS are related to the amplitude of external magnetic field and the frequency. Through this study, we find that it is possible to apply the results by Magnetization. Technique to the AC power system, to the design of AC machine, to design of HTS proper to the foretold AC losses.

자성체를 포함하는 자기 시스템을 해석하는데 있어 비선형과 히스테리시스(Hysteresis)는 매우 중요한 역할을 한다. 특히 재질의 히스테리시스 특성을 유한요소법(FEM)을 이용하여 계산하기 위해서 많은 방법들이 소개되었다. 단순 반복법이나 Fixed Point Technique(FPT), Miteration 법. 뉴튼 랍슨 (NewtonRaphson) 법 등이 그 예이다. 이 방법들 중에서 뉴튼 랍슨법은 빠른 수렴 특성으로 가장 많이 사용되고 있다. 하지만 뉴튼랍슨법을 이용하여 히스테리시스 재질을 해석할 때는 매 반복 계산 때마다 계 계수행렬(System Stiffness matrix)이 변화하기 때문에 요소의 수가 매우 많을 경우 역행렬을 계산하기 위한 시간이 많이 소요되는 단점이 있다. 특히 히스테리시스 해석의 경우에는 주로 timestep법을 이용하여 계산하므로 가장 시간이 많이 소요되는 행렬 계산 시간을 단축함으로써 전체 계산 시간을 크게 줄일 수 있다. 최근 비선형 해석에서 TLM(Transmission Line Modeling)법이 도입되어 비선형 해석 시의 계산 시간을 크게 단축할 수 있게 되었다. 본 논문에서는 비선형 해석에 적용된 TLM법을 히스테리시스 해석에 적용하는 방법을 새로 제안한다. TLM법은 뉴튼랍슨법과 달리 각 반복 계산 때마다 계수행렬식이 변화하지 않고 단지 구동항만 변하기 때문에 행렬의 LU를 한 번 저장해 두면 forward와 backward substitution만 시행하면 된다. 따라서 요소의 수가 증가할 경우 TLM법을 사용하면 뉴튼랍슨법에 비해 매우 큰 계산 이득을 얻을 수 있다. 본 논문에서는 TLM법을 히스테리시스에 적용하는 방법을 기술하고 간단한 모델에 이 방법을 적용하여 뉴튼랍슨법과의 비교를 통해 TLM법의 효용성을 보인다.

This paper describes BIEM(Boundary Integral Equation Method) for computation of three dimensional electric field distribution and numerical method that an equivalent charge density is unknown variable. After computing numerically the surface charge distribution. the distribution of both potential and electric field are obtained. Finally, this numerical method is applied to the concentric sphere and the coaxial cylindrical model and numerical result is compared to the analytic solution.

In this paper, a numerical analysis algorithm of eddy current testing(ECT) for heat exchanger tube with axisymmetric defects using finite element method(FEM) is presented. In the ECT FEM analysis, we used trianglular and rectangular elements for exact signal of ECT for variable shape of defects. This paper presents a systematic and efficient numerical analysis algorithm for ECT. We employ the LU decomposition and Cholesky method for solving the system matrix. This numerical analysis algorithm is effectively applied to heat exchanger tube with defects.

The round HTS wire is easier to handle than the rectangular HTS tape. This paper describes the coupling losses of the round HTS wires by finite element method. Effect of filament arrangement and filament size of the round HTS wire are considered. Three types of filaments arrangement, one and double layer radial filaments and Multifilament, are considered. Calculation results show that coupling losses of the one layer filaments round HTS wire vary only a little with the direction of external magnetic field.

Capacitorrun single induction motors have the unbalanced elliptic rotating magnetic field so that it is difficult to analyze the characteristic and calculate the accurate slot leakage reactance of the rotor with the closed slot by using the lumped parameter. In this paper, the characteristic is analyzed by the symmetrical coordinate method in terms of the lumped parameter coupled with the numerical analysis. The secondary parameters are calculated by the one slot pitch boundary condition applying to Finite Element Method (FEM). The analysis results are compared with experimental ones.

DC모터의 TN(토크회전수)특성이 선형성을 갖는다는 사실은 널리 알려져 있다. 더욱이 인덕턴스가 작은 소형 모터의 경우에는 TN특성이 거의 직선에 가깝게 된다. 그러나 대형모터일수록 인덕턴스가 커지므로 이 인덕턴스의 영향으로 TN특성은 비선형의 곡선으로 변하게 된다. 이렇게 되면 모터의 출력은 직선으로 예측하였을 때 보다 실제적으로 작은 출력이 발생하게 된다. 따라서 일반적으로 DC모터를 설계할 때 TN특성의 비선형화로 인한 출력의 감소현상을 고려하여 임의의 여유를 주고 설계하여 왔다. 그러나 효율적인 모터설계를 위하여서는 임의의 여유가 아닌, 이론적 계산에 의한 정확한 TN특성의 곡선을 필요로 하게 된다. 하지만 아직까지 이를 위한 용이한 계산법은 마련되어 있지 않다. 따라서 본 논문에서는 matlab을 이용하여 DC모터의 비선형 TN곡선의 계산법을 도출하여 그 방법을 제시하고자 한다.

Many linear motion devices in industry require a limited movement in which the moving member oscillates. Such motion is often governed by a prescribed distancetime relationship.

In the early development of wind energy, the majority of wind turbines were operated at constant speed. Recently, the number of variablespeed wind turbines adopted pitch control apparatus has increased. This paper deal with a simulation of pitch control of variablespeed wind turbine and the response of pitch angle is traced in a given random wind speed.

The value of
$I_c$ (critical current) in HTS (High Temperature Superconductor) tape has a great influence on$B{\bot}$ (vertical field). Therefore, in shape design of field coil for the HTSG(High Temperature Superconducting Generator), a method to reduce the$B{\bot}$ should be considered in order to maintain the stability and substantial improvement on the performance. On the basis of the magnetic field analysis, this paper deals with various field coil shape to obtain small$B{\bot}$ by using BiotSavart's law and image method. Moreover the analysis is verified by comparison with experimental results. And also this paper presents the advanced model by using 3D FEM(3 Dimensional Finite Element Method), in which flux density at armature is calculated in 5kVA class HTSG. 
The paper is described about the statatic and dynamic characteristics analysis of Transverse Swithed Reluctance Motor(TSRM). To investigate the nonlinearity of magnetic circuit, parameters of the modeling are computed by the finite element method as functions of input current and angular displacement. The current, torque, back EMF and output power wave of TSRM are simulated from the motion equation by MATLAB/Simulink.

Brake system using eddy current is adequate to obtain safe braking force in high speed transportation system and electric vehicle etc. In this paper, we propose the new type eddy current braker using Halbach array. which compared with the conventional permanent magnet array. The airgap flux density of Halbach array is higher 25% then conventional array, therefor we can predict that braking force is much large 1.56 times then conventional array.

Recently, optical pickup actuators have been designed to have structures that extruded lens to decrease their height, because they are used in very thin drive for notebook computers. However because of discordant and undesirable of forces that are supposed to happen in this design feature, subsidiary resonance such as rolling and pitching mode exert bad influence on actuator. In this paper, we presented force constituents to clarify the cause of subsidiary resonance analysis to evaluate characteristics of actuators. As a result. we could find out design parameters to diminish the influence of subsidiary resonance. Sample actuators designed with appropriate parameters were fabricated and put to practical tests. Comparing analysis with experimental results, we verified the accuracy of the analysis and the effectiveness of the method presented.

The rotor of the BLDC motor has permanent magnets on its surface, and is alike the structure of the rotor of synchronous motors. When designing the BLDC motor which has a limited volume in a specific environment, it is important to consider the geometry of the rotor and the length of the airgap. This paper describes a design procedure by analyzing the induced voltage and cogging torque with changing the width of magnets and length of the airgap. And we made a prototype of BLDC motor with this design procedure and our experiment result shows that the cogging torque can be reduced significantly. Also we find a good agreement between the result of experiment and simulation values using Finite Element Analysis.

In the slotted motor, cogging torque is generated due to the interaction between the rotor magnets and the slots on the stator. It is well known that cogging torque produces vibration and noise which may be detrimental to the performance of position and speed control system. Hence, the prediction of cogging torque is very important at the design stage of BLDC motor. In this paper, permanent magnets with different arc an91e of inner and outer radius is proposed. The cogging torque of proposed model and conventional one is analyzed by 2D FEM and compared.

This paper describes the steady state performance of a selfexcited wound type induction generator with stator and rotor windings connected in series along with excitation capacitors. For this purpose a mathematical model is developed by means of the well known generalized machine theory utilizing dq axis orthogonal transformation. This model can be used to analyze short shunt and long shunt generators as well as shunt generator and the algorithm for this analysis is persented. The characteristics of generators are compared one another by using parameters which are validated by Mostafa et al.

This paper deals with the effect of rotor thickness variation and winding method in high torque hybrid Permanent Magnet(PM) step motor. As these parameters vary. The flux distribution in airgap and torque characteristics are influenced, which is related to output power. efficiency and cost. These parameters and characteristic variations were evaluated by using Finite Element Method (FEM) and experiment method. From these results. Characteristic analysis for the optimum design was studied and prototype motor was made to test performance analysis.

The self and mutual winding inductances can have an important influence on both the steadystate and transient dynamic performance of a machine. Especially, slotless topologics have inherently low self and mutualstator winding inductance. Thus, this paper describes an analytical model for predicting the winding inductance and results are compared to finite element analyses.

In this paper, the characteristic of the Linear DC motor(LDM) are analyzed by using 3 Dimensional Equivalent Magnetic Circuit Network (3D EMCN), the movement of mover substitutes for the movement of magnetization in permanent magnet expressed by Fourier series, thrust characteristic analysis is performed and the appropriateness of analysed result is verified by comparing with the results of 2 Dimensional Finite Element Method (2D FEM) and experiment.

This paper treats the electromagnet type linear synchronous motor with induction operation. The proposed motor consists of the primary winding energized by variable frequency supplies and the secondary having an additional solidconductor besides the field finding. The conductor is useful for not only the selfstarting but also the damping effect In the synchronous drive. From the investigation by the experiment and the finite element analysis coupled with both electric circuit and motion equation we verify that the proposed motor is effective for practical use.

This paper deals with the effect of teeth width variation in Permanent Magnet DC motor. As teeth width varies, effective flux density is influenced, which is closely related to torquespeed characteristics, output power, and efficiency of the motor. In this study. motor design was carried out using finite element method with various teeth width. Prototype motors under constraints of same armature diameter, material and axial length were made and their performances were tested.

The paper proposes the characteristic analysis method to consider the saturation of teeth and poles in the hybrid stepping motors. The proposed method is based on the equivalent magnetic circuit coupling with the finite element analysis. The equivalent magnetic circuit is used to analysis the characteristics of the hybrid stepping motors. And the FE analysis is used to compute the nonlinear parameters included the equivalent magnetic circuit in the hybrid stepping motors. Simulation and experiment results show that the proposed technique is compared with the classical method.

This paper deals with characteristic analysis of Permanent Magnet Linear Synchronous Motor(PMLSM) and Linear Reluctance Motor(LRM). PMLSM and LRM can be classified into the short primary type and the short secondary type according to their structural features. In this paper, select the short secondary. Thrust and lateral force are evaluated by using Finite Element Method(FEM) and experiments. These characteristics of PMLSM and LRM are compared with each other.

Because of linear operation by direct drive and compact system, and the free accumulation of position error, LPM is suitable for proportional control valves actuator. In this study, to develop electromagnetic proportional valves actuator we designed tooth shape of double sides LPM and suggested the driving principle based upon the excitation method, It's the magnetic structure is so complex by the cubic effect configuration that finite element analysis is required. By the 3D finite element analysis, we got the magnetic distribution of LPM and analyzed static thrust force characteristics. By this analyzation, we obtained basic data required for the practical use of driving system for the proportional control valves. Thus, considering electrical and mechanical constants we could design and manufacture double sides LPM for the proportional control valves.

In this paper, we have designed the advanced DVT HLSM inserted a permanent magnet into the slot in order to improve the thrust force without increasing the normal force. And it was analyzed the characteristics of thrust force and normal force of the new HLSM by using Finite Element Method and Virtual Work Method. As a result of this paper it was confirmed that the thrust force characteristics of the new HLSM improved about 23% in comparision with DVT HLSM without increasing the normal force.

This paper deals with the dynamic characteristic analysis of Linear Oscillatory Actuator (LOA) considering Sine Pulse Width Modulation (SPWM) method with Hbridge driver. The input current shape obtained by the driver has great influence on the driving performance of LOA. Therefore, according to the various current shapes, the analysis is achieved by using the combined equation between kinetic and electric circuit equation. Moreover, the parameters in the electric circuit equation are accurately estimated by using FEM.

A movingcoiltype linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coilwrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The inductance of moving coil and the push/pull effect is obtained from the permeance model of LOA with the open magnetic circuit. The analytical method are verified using the 2D finite element method.

For an accurate analysis of three dimensional linear magnetostatic problems, a new boundary integral equation formulation is presented. This formulation adopts difference magnetic field concept and uses single layer magnetic surface charge as unknown. The proposed method is capable of eliminating numerical cancellation errors inside ferromagnetic materials. In additions, computing time and storage memory are reduced by 75% in comparison with the reduced and total scalar potential formulation. Two examples are given to show its efficiency and accuracy.

This paper presents dynamic modeling and simulation of induction motors. Equivalent circuit parameters measured by do test, noload test and lockedrotor test were used as the input data for computer simulation. Operating characteristics of an induction motor were predicted by Matlab/simulink when changing load torque, opening and reclosing of phase a of the stator and threephase fault at machine terminals.

This paper introduce of program package for the numerical analysis of Electromagnetic field analysis using Finite Element Method, called Electro Magnetic Field(EMF). This software tool is developed by Changwon Nat'l Univ. cooperative with Hanyang Univ. and produced on a commercial scale. EMF has a simple, easy to use graphical interface which steps user through th problem setup, high accurate solution, and fast computation.

This paper present recent the KEPCO's substation power transformer status and power transformer fault analysis by the fault part, the cause of fault, the manufacture etc.

This paper presents the maintenamce method of transmission power transformer by Korea Electric Power Corporation. Also, this paper presents preventive diagnostics method for power transformer and introduce the new preventive diagnostics method for power transformer.

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. In this research, the principle of the interrupting techniques are given and experimental results of hybrid interrupter which is developed by new technology is introduced.

We worried about the technology difference between our company and the advanced companies at present motor market. Thus we started independently to develop the technology of motor coil insulation system and to accumulate insulation technology data. When we export the electric machines to oversee market. we are asked to set up the insulation system to show our product excellence. We first evaluate the insulation system of our motors to realize higher reliability of high voltage insulation system. Therefore we are possible to do the insulation diagnosis in real site and have accumulated the data related in insulation diagnosis. Thus we have improved the our insulation system. And also these data were used to new product development as very useful data. also will be used the insulation deterioration diagnosis to estimate the remained life time which is very important data for the maintenance management. As the result. we are able to get the our product reliability.

We fabricated a resistive superconducting fault current limiter of meander type based on a YBCO film. In order to disperse the heat generated at hot spots in the YBCO film the film was coated with a gold shunt layer. When diodes were inserted in the parallel circuit to restrict the temperature increase in the SFCL element by reducing power supply cycles, the voltage could be increased to
$\sqrt{2}$ times with the same quench resistance at a half and full cycles. 
교류전력을 측정하기 위하여 알고 있는 직류전력과 동시에 비교할 수 있는 전력비교기를 개발하였으며 이 비교기를 기본으로 하여 정밀 전력계와 전자식 전력량계를 교정하거나 시험검사 할 수 있는 기준시스템인 전력표준기를 개발하였다. 특히 PushPull 기술을 이용한 전력비교기는 간단하며 정확도가 매우 높은 것으로 평가되었으며 전력비교기의 전체 불확도는 30
$\mu$ W/VA로 평가되었다. 
Bi2223 테이프의 실제 전력기기 응용측면을 고려할 때 테이프는 외부자계하에 놓이게 된다. 따라서 본 연구에서는 외부자계가 Bi2223 테이프의 통전손실에 미치는 영향에 대해서 조사하였다. 비교적 작은 자계가 인가된 경우는 전압리드의 배역이 통전손실측정에 영향을 미쳤으나 비교적 큰 자계가 인가된 경우는 전압리드의 배열에 무관하다는 사실과, 전계와 통전손실은 외부사계가 증가함에 따라 각각 증가하였으며 비교적 큰 자계가 인가된 경우에 통선손실은 동저항 손실이 지배적이었으며. 외부자계가 작은 영역에서 통전손실은 동저항 이외의 또 다른 메카니즘에 의한 것으로 사려된다.

This paper presents the design of a double pancake winding type high
$T_c$ superconducting power transformer In the design of the transformer. BSCCO2223 tape was considered as the conductor. Double pan cake winding was adopted in order to easy the construction of the winding and to lessen the leakage reactance of the transformer. Numerical calculation was used to decide the arrangement of the double pan cake winding. Room temperature bore type cryostat has been constructed and its heat loss was estimation. 
The preventive structure of field lead connector's Vnotch on synchronous generator has been developed. The preventive structure of field lead, installed in the generator, prevent from V notch of field lead connector in rotor on daily start and stop (online). This development of study was performed at the Seoinchon combined cycle power plant on gas turbine generator. This preventive structure of field lead will be prevent from Vnotch of field lead on synchronous generator's field.

전기설비에 있어서 저압회로의 과전류 보호기기로는 배선용 차단기, 기중 차단기, 한류 퓨즈, 전자 개폐기 등이 있으며, 이중 배선용 차단기의 중요한 차단원리인 한류차단원리 및 현상에 대해 상세한 분석이 필요하다. 단락이 발생하면 상당히 큰 단락전류가 흐르게 된다. 이 단락전류를 차단하는 경우 단락전류를 그대로 흐르지 않게 하여 본래의 단락전류를 작게 제어하면 차단시의 에너지는 작아진다. 본래의 단락전류를 작게 억제하여 차단하는 방법을 한류차단방식이라 하며 이러한 기구를 한류기구라 한다. 한류차단방식을 채용함으로써 동일 치수의 차단기라면 보다 큰 단락전류를 차단하는 것이 가능하다. 여기서는 한류차단특성의 이론적 해석과 단락전류에 의한 전자기적 영향, 기계적인 영향, 열적인 영향을 설명하고 이러한 영향을 최소화하기 위한 한류차단 원리 및 방법을 설명하고 분석하고자 한다.

In this paper described that study on the distribution and characteristics of axial magnetic field by mathematical analysis and experiment for axial magnetic field type vacuum interrupter that important part on vacuum circuit breaker. And, it was shown that inspected results of arc shape at breaking the current by typical axial magnetic field type model and new axial magnetic field type model.

Recently, the reliability of switching devices for transmission & substation system is very important. Especially, the use of Gas Insulated Switchgear increase gradually. Therefore, We have investigated the fault trend of Gas Insulated Switchgear from 1985 to 1999. This paper presents the fault analysis on 154 kV, 345kV Gas Insulated Switchgear, including 25.8kV Gas Insulated Switchgear. Thus, this paper will help improve design, manufacture, construction technology and maintenance method.

In order to design thermally trigger controlled persistent current switch(PCS) for MRI magnet system, it is very important to know informations of applied adiabatic method and condition to get designed resistance and characteristics. Adiabatic part of PCS is consist of cottongummed tape and cryogenic stycast. This adiabatic method has the advantage of continuously winding superconducting and adiabatic part of PCS and reducing the time of manufacture. We experimentally derived averaged thermal conductivity on the assumption that shape of adiabatic part of PCS is that of pipe. In result, averaged thermal conductivity is about 0.29 W/m K and designed value is very satisfied with actual experimental data.

In the cleaningwater treatment process, the flocculation machine is operated by the V.S motor when the coagulationfacility of the coagulationprocess is operated. But after the flocculation machine is stopped by an instantaneous power failure, the transient takes place when the coagulation facility is restarted. To improve the transient state, we developed the reinforcementcircuit which had the function of softstart and adapted to the field. As a result of this study, we reduced the damage of facilities and had the safety in maintaining the quality of water and improved the efficiency in the maintenance and the management.

This paper has explained a various excitation mode to analyze the torque performance of SRM. The simulation results show that 3phase square excitation mode models have revealed high torque performance.

In this material, the characteristics and types of the electric propulsions for ships are examined and compared. And a trend on the technical developments of electric propulsion systems for ships are examined. So, this material will be a few helpful in researching and developing the electric propulsions for ships.

Most of the application standard of the lowvoltage devices have applied one the IEC standard another the UL standard. European union applied the IEC609471 standard has not exceed 1000V a.c. or 1500V d.c.. Therefore. it is necessary to the lowvoltage device has expended for rated operational voltage with our products. The export of European market shall be made for the CEMarking in accordance with IEC609471 ( Lowvoltage switchgear and controlgear). We shall be considered for the requirement with the IEC standard. In this time to study for power supply system at EU ( European union. At that time for design and development in order to the construction and test method among the study for the rated insulation voltage at less then 690V.

비등방성 고온 초전도 테이프는 자장의 세기뿐만 아니라 방향에 따라서도 임계 전류 값이 영향을 받는다. 이러한 비등방성 고온 초전도 테이프로 권선된 솔레노이드 마그네트의 임계 전류 특성 및 임계 전류를 결정짓는 위치를 알아내기 위해, 솔레노이드 모델의 자장 분포 및 수직 자장 성분과 평행 자장 성분을 구하고 임계 전류는 비선형 방정식을 수치적인 방법을 이용하여 예측해보았다.

This paper deals with characteristics analysis of DoublyFed Induction Generator (DFIG) in the supersynchronous speed regions. by control of voltage fed to the rotor using for bidirection control. This rotor voltage is controlled by con troll of inverter switching frequency and fire angle. Characteristics of DFIG is analyzed by steadystate algebraic equations of the equivalent circuit using numerical analysis. And it is compared with results of experiment. Consequently, this paper presented to find the optimal magnitude of voltage fed to the rotor for maximum power and PF, using result of characteristics analysis.

In this paper, we describe the starting and synchronizing methods in the linear induction synchronous motor. The proposed motor consists of one pair of linear synchronous motors (LSMs) and an additional linear induction motor (LIM). The primary cores have a common ring winding, and solid conductors are arranged in both LIM and LSM. From the investigation by analysis and experiment, we verify that the proposed motor is effective for practical use.

Application of Linear DC Motor is spreading fast in OA and FA systems due to simplicity in structure, highspeed operation and highprecision positioning. In this paper we have measured and monitored some characteristics of Linear DC Motor. We used LabVIEW software to construct Linear DC Motor Monitoring system.

Sensorless PMSM is much studied for the industrial applications and home appliances because, a mechanical sensor reduces reliability and increases cost. Two types of instantaneous torque controls are basically used for high performance variablespeed a.c. drive : vector control and direct torque control. This paper investigates speed sensorless control of PMSM using direct torque control. The switching of inverter is determined from SVPWM realizing the command voltage which is obtained by flux error and measured current without dq transformation. The rotor speed is estimated through adaptive observer with feedback loop. The simulation and experimental results indicate good performances.

Linear induction motors have static and dynamic end effects due to its finite core length, so that perphase impedances are asymmetric and the air gap flux distribution is distorted. Because of these points the dq equivalent circuit model considering both end effects has not been exactly completed. So this paper proposes a characteristic analysis method considering both static and dynamic end effect of the LIM. This method is to utilize asymmetric dq equivalent circuit model with dynamic end effect coefficient. As a result, it is shown that the simulation results have a good agreement with experimental ones.

In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In the paper, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

This paper presents the software control of a brushless DC motor. Not only speed and current controls but also a realtime identification of the motor parameters can be implemented by software using the digital signal processor (DSP) TMS320F240. The DSP Controller TMS320F240 from Texas Instruments is suitable for a wide range of motor drives. TMS320F240 provides a single chip solution by integrating onchip not only a high computational power but also all the peripherals necessary for electric motor control. The main benefits are increased system reliability and cost reduction of the overall system. The present paper describes how a speed controlled brushless DC drive can be implemented using TMS320F240.

The paper presents the software control of a brushless do motor with parameter identification. Not only speed and current controls but also a realtime identification of the motor parameters can be implemented by software using the digital signal processor TMS320F240. The DSP Controller TMS320F240 from Texas Instruments is suitable for a wide range of motor drives TMS320F240 provides a single chip solution by integrating onchip not only a high computational power but also all the peripherals necessary for electric motor control. This new family of DSPs enables single chip, cost effective, modular and increased performance solutions for BLDC drives. The present paper describes how a speed controlled brushless DC drive can be implemented using TMS320F240 and what kind of results can be achieved.

Switched reluctance motor generally operates in the magnetically saturated region because the saturation gives several benefits to its performance. This paper investigates the modelling and fuzzy tuning PI control of a nonlinear switched reluctance motor. The modelling is performed through neural network technique. Fuzzy autotuning PI control is designed for a robust performance in load and speed variations. Simulation and experimental results indicate better performances compared with simple PI control.

BLDC Motor has many advantages for control. This paper presents to perform constant speed against disturbance during operation. BLDC motor control used IP algorithm to have fast response, reliable stability and robust response. In this paper IP algorithm applied to 50W BLDC Motor According to results, IP algorithm characteristics is confirmed.

SRM(Swithed Reluctance Motor)은 회전자 위치와 동기 되어 여자 되어야 한다. 이러한 토오크 발생기구의 특성상 회전자 위치각에 대한 정보가 필수적이다. 회전자 위치각의 검출은 일반적으로 엔코더나 레졸버를 사용하나, 본 연구에서는 저 분해능 엔코더를 사용한 경우에도 고정도의 온, 오프 스위칭. 각을 제어하기 위해서 미소각 예측 및 미래 지향적 스위칭각도 제어기법을 제안하였다. 또한 이를 프로토 타입으로 구현하기 위해서 89C196의 HSO(High speed output) 기능을 사용하였다.

The switched reluctance drive provides a good adjustable steed characteristics like a D.C series motor. However, because of the torque production mechanism, it also has some disadvantage such as higher torque ripple and fluctuation in speed. To reduce torque ripple and to control speed precisely at low condition current level technique is adopted. The SRM drive with current control of invariable frequency and phase swichting control has good speed regulation characteristics. Digital control system with an 80c196kc microcontroller is used to realize this drive system. Test results show that the control system has the goof ability to achive precise speed control at low speed.

In this material, a traction motor for light railway vehicle was developed. Aluminium Diecasting process was selected in order to reduce the manufacturing cost of making rotor bars and rotor rings of the motor, instead of copper or copper alloy rotor bars and rotor rings. And the results of experiment satisfied the international standard IEC 3492.

본 사이트에서는 국산 공학 소프트웨어를 주력으로 판매하고 공학에 관련한 일반 상용 소프트웨어를 판매한다. 또한 공학자들의 전문적인 공간으로서 국책/기업 연구소, 정부기관, 대학교 연구기관과 링크를 통해 고객 서로가 자료를 공유할 수 있는 사이트로 활용하는데 목적을 둔다.


According to the importance of the earth environmental issues, the study of low emission vehicle is achieved actively throughout the world. It is studied for electric motor to be contented with the characteristics of electric and hybrid vehicles in this paper. It is represented for the result of design, analysis manufacture and test of the motor for electric vehicles.

In the operation and maintenance activity of hydro turbine generator, one of the important parameters is the efficiency. This study analyze the case of efficiency management by pressure time method and survey the application of this method through the actual test. And it is confirmed that the Pressure time method exccesively limit the general condition to be applied. If index method is used for efficiency management because the index method calibrated by absolute discharge(by flow of pressure time method) is very accurate. it make to be able to manage the realtime efficiency.

This paper presents the preventive measure and the cause for field coils breaking away from the rotor, which lately occurred when No.1 hydro generator was operating in ChungJu Dam No.2 Hydro Power Station. In findings, we ascertained the truth of contact between rotor rim and field coils, and think that field coils will break away from the rotor because of mechanical stress according as continuous operation after completion. 1985. Therefore, we conclude that the preventive measure for such a phenomenon is that stopper should be installed between rotor rim and field coils, and bolts should be tightened because of operating characteristic however there are not the design standards for installing stopper in generator rotor internationally.

Electric vehicle(EV), hybrid electric vehicle(HEV) and fuel cell electric vehicle(FEV) are seen as one way of reducing the harmful effects of traffic and of improving energy efficiency. Therefore the status and developing trend of the EV, HEV and FEV are given in this paper. A major aspect of alternative drive trains is the electric drive train. The automotive aspect in developing electric drive trains is emphasized.

Direct torque control algorithm for 3level inverterfed induction motors is proposed. Conventional selection method of the stator voltage vector shows problems of stator flux drooping phenomenon and undesirable torque control appeared especially at the low, speed operation. To overcome these problems, a proposed method uses intermediate voltage vectors, which are inherently generated in 3level inverters. An adaptive observer is also employed to estimate some statevariables and motor parameters, which takes a deep effect on the performance of the low speed operation. Simulation and experiment results verify effectiveness of the proposed algorithm.

This paper presents and analysis a system control algorithm of direct torque control for induction motor using digital signal professor. Using direct torque control, robust. simple and dynamic motor control can be realized. The implemented system is verified by analyzing control torque and flux characteristic.

This paper presents an implementation of digital motion control system of induction motor vector drives with a direct torque control(DTC) using the 16bit DSP TMS 320F240. The DSP controller enable enhanced real time algorithm and costeffective design of intelligent controllers for induction motors which can be yield enhanced operation, fewer system components, lower system cost, increased efficiency and high performance. The system presented are stator flux observer of current model that inputs are current sensing of motor terminal and rotor angle, and optimal switching lookup table by using fully integrated control software. The developed system are shown a good motion control response characteristic results and high performance features using 2.2Kw general purposed induction motor.

To obtain a high performance in a vector controlled induction machine, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly varies due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. This paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque command current produced by speed controller is utilized for the rotor resistance estimation. This method has advantages with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations.

Speed control without speed sensor is expected strongly to progress reliability, simplicity and cost performance of I.M and to expand its application part. This paper investigates a novel speed estimation method of I.M considering the secondary resistance identification based on the transientless torque control technique. Especially, this paper aimed at the identification of the secondary resistance simultaneously with speed estimation. For this, the secondary flux with some frequency is controlled independently on torque. The proposed speed estimation method is derived from a motor circuit equation theoretically and also it can be conducted easily by detecting primary motor currents and primary voltage commands at every sampling time. Some numerical simulations with the assumption of using a pulse width modulation(PWM) voltage source inverter and experimental results are performed to verify the proposed method.

A direct torque control(DTC) based sensorless speed control system which employs a new closed loop flux observer is proposed. The flux observer is an adaptive gain scheduling observer where motor speed is used as the scheduling variable. Adaptive nature comes from the fact that the estimates of stator resistance and speed are included as observer parameters. Simulation results show that the proposed flux observer gives better control and estimation results than conventional flux estimator specially in low speed region.

An investigation into power conditioners that interface with photovoltaic array and utilities has been completed. The rating for this investigation is residential system (35kW) that interface with a 220V single phase utility connection. As the result of this investigation. a 3kW high frequency PWM IGBT inverter feeding a high frequency isolation transformer with a sinusoidal current wave was selected. The output of the transformer rectified with a diode bridge rectifier four IGBT, used as 60Hz switched, reverse the polarity of the rectified current on every other half cycle of the utility voltage. Even though the high frequency link system used more power semiconductors, a net size, weight, and parts cost saving result compared to the other systems due to elimination of 60Hz transformer.

This paper describes a new approach to estimating permanent magnet synchronous motor(PMSM) speed and position from measured terminal voltages and currents for speedsensorless vector control. The proposed system is based on observing the instantaneous reactive power of the motor. The described technique is very simple and robust to variations of motor parameters. The new approach is not dependent upon the value of the stator resistance. Also, MRAS schemes are chosen for determining the adaptive law for the speed and the position estimator. The effectiveness is verified by simulation.

Deadbeat technique has been proposed as a digital controller for an UPS inverter to achieve the fast response to a load variation and to conserve a very low THD under a nonlinear load condition. This scheme contains a fatal drawback, sensitivity against parameter variation and calculation time delay. This paper proposes a second order deadbeat current controller, which fundamentally solves the calculation time delay problem and certainly guarantees the robustness of the parameter's variation. This is shown theoretically and practically through simulation and experiment.

본 논문에서는 속도검출기가 없는 표면부착형 영구자석 동기 전동기의 속도제어 기법을 제안한다. 표면부착형 영구자석 동기 전동기는 그 형상에 있어서는 자기적 돌극성을 가지지 않지만 기본 주파수에 비하여 높은 주파수를 가지는 전압을 전동기의 추정된 회전사의 위치와 같은 축에 인가함으로써 자속의 포화에 의한 고주파 임피던스의 차이를 관측할 수 있다. 본 논문에서는 이 고주파 임피던스의 차이를 이용하여 전동기회전자의 위치를 추정하고, 추정된 회전자의 위치를 이용하여 속도 및 위치 검출기가 없이도 벡터제어를 수행한다. 또한, 이 고주파 임피던스의 특성은 부하조건에 따라 변하기 때문에 추정하는 회전자의 위치가 부하조건에 따라서 왜곡된다. 본 논문에서는 회전자의 위치를 추정한 후 부하조건에 따라 회전자의 위치를 보정하는 기법도 제안한다. 마지막으로 실험을 통하여 제안된 기법의 타당성을 검증한다.

본 논문은 위치 및 속도 검출기가 없는 매입형 영구자석 전동기(interior permanent magnet motor, 이하 IPMM)의 위치 제어 기법에 관한 것이다. IPMM은 기본적으로 자기적인 돌극성(magnetic saliency)을 가지고 있지만, 그것은 부하 조건에 의해 쉽게 변하는 특성을 가지고 있기 때문에 제어 성능이 쉽게 떨어질 수 있다. 본 논문에서는 기존의 방법과 같이 그 돌극성. 혹은 임피던스 차이를 이용한다. 하지만, 회전자 위치 정보를 나타내는 임피던스 차이를 극대화하고 어떤 부하 조건에서도 성능을 유지하기 위한 고주파 신호 주입 방법이 제안된다. 제안된 방법은 IPMM의 위치 및 속도 검출기가 없는 센서리스 제어를 가능하게 한다. 단위 전류 당 최대 토오크 제어도 제안한다. 제안된 방법을 위해 다양한 부하 조건에서 IPMM의 토오크와 고주파 임피던스 특성을 분석한다. 그 특성을 기본으로 하는 속도 및 위치 추정 방법을 제안한다. 제안된 방법은 회전자 위치와 관련된 고주파 임피던스 성분을 추출한다. 실험 결과를 통해 여러 부하 조건에서 제안된 방법의 성능을 확인하였다.

This paper describes performance analysis of ARCP Inverter, which can offer zero voltage switching at nominal voltage stress. The system consists of a voltagesource inverter with sortswitching module. Each main switch is connected in parallel with resonant capacitor and two auxiliary switches are placed in series with a resonant reactor for softswitching capability. The described ARCP inverter could be effectively applied for active power filter reactive power compensator, and UPS.

Rim, GeunHie 1067.1
During the last three decades power electronics has gone through energetic technical evolution. The technical needs from wide area such as in industrial, commercial, consumer, aerospace and environmental applications have driven the environment favorably for the power electronics. In the future, two extreme technologyexpansion trends are expected: one into low power, and the other into very high power. The former is based on the high frequency and the circuit miniature using VLSI circuit and surface mounting aiming for the systemonchip (SOC) technology. The latter includes the application areas of power utility such as HVDC, FACTS and SVC and large science area of electrophsycal apparatus such as thermonuclear fusion, acclerators, and electric guns. This paper describes the technology status of some major elements which are available today and the key roles of the power electronics from view points of applications. The author would like to take this opportunity to raise discussions about the future technology development trend of power electronics in our country with the fellow power electronics engineers. 
This paper presents a method of designing the control loop for dctodc converters when at characteristics of the converter's load are unknown. In the proposed method, a converter is considered as a standalone module that feeds a current sink load, and the control loop is designed in order to maximize the robustness of the converter's closedloop performance. The proposed method yields a control design that provides predictable and controllable closedloop performance for the converter loaded with an actual load.

The use of HDL(Hardware Description Language) is now central to the ASIC(Application Specific Integrated Circuit). HDLbased ASIC can simplify the process of development and has a competition in market because it reduce the consuming time for the design of IC(Integrated circuit) in system level. Therefore, the development of power electronics system on chip (SOC), to design microcontroller and switching logic as one chip, is required extremely for the purpose of having reliability and low cost in power electronics which is based on switching elements. The major application of SOC is variable converter, active filter inverter for induction motor. UPS and power supply with a view to reducing electromagnetic pollution.

This Paper reports on an experimental and theoretical work about self exited HalfBridge inverter for contact less battery chargers. The steady state characteristics of inverter are analysis and the experimental result for 500kHz, universal AC source input have been obtained. These inverter is suitable for the portable appliances with battery chargers such as cellular phone.

In this paper. the design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant including the controller. This means that the relation between the filter capacitor value and the system time constant is given as the closed form. By using the above closed form. the capacitor value can be calculated with the system time constant which can be implemented practically not using the try and error method. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it can be verified how much the voltage distortion is effected when the nonlinear load is connected.

본 연구에서는 부하의 급격한 변화 또는 병렬컨버터를 구성하는 단위컨버터의 고장 발생 시 안정적인 병렬컨버터의 운용을 위한 연구를 수행하였다. 단 위컨버터는 응답특성을 개선하기 위하여 평균전류모드제어를 채택하였으며, 병렬컨버터의 부하전류분담을 위하여 최대전류 제어법을 이용하였다. 병렬컨버터의 모델을 도출하여 부하전류분담 제어에 따른 동작특성을 분석하였다. 급격한 부하변화와 단위컨버터의 고장발생 시 안정된 병렬컨버터의 특성을 실험을 통하여 확인하였다.

In this paper a development of 10KVA seriesparallel compensated UPS is shown, which has high input power factor and sinusoidal output voltage regulation capability. Compared to conventional cascaded UPS, the size can be reduced significantly with high quality input and output waveforms. The front converter and the main inverter can be considered decoupled, hence the front converter and the main inverter can be designed independent of each other. In this paper, analysis and experimental results for an 10 KVA prototype are presented.

T5 형광등용 안정기 제품에 대한 성능을 고찰하기 위해 T5 형광등에 대한 정확한 이해와 함께 대표적인 안정기회사들의 제품에 대해 광출력에 대한 특성, 고조파 및 역율등 전기적 특성 기타 특성등에 대해 시험하여 분석하였다.

철강 생산라인 중에서도 핵심적인 열간압연 라인의 연속 사상압연 공정을 소개하고 스탠드간에 위치한 루퍼의 각도 제어와 장력제어의 상호 관계를 설명하였다. 또한 압연용 전동기 속도 제어계 특성의 설계법을 보였다. 이와 같은 연속 압연 공정에서는 철판이 여러 압연기에 동시에 물려있는 상태로 운전되므로 인접한 압연기들의 속도 제어 응답성이 동일한 특성을 갖는 것이 필요하다.

In this paper, describes a rotor speed identification method of induction motor based on the theory of counter EMF MRAS. This method eliminated the pure integrator and we can be expected to rapid responsibility of the speed identification. Therefore, we may improve the initial condition of the integrator and drift problem. The stability of speed estimator is proved on the basis of hyperstability theory. In order to confirm the performance of the proposed system, simulation and experiment is performed.

This paper proposes a tension control to compensate friction loss using online friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension. accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The experimental results show improvement of tension control performance by the proposed friction compensation method.

ASIC chip design for motor control has been a subject of increasing interest since an effective methodology of systemonachip design was developed. This paper investigates the design and implementation of ASIC chip for vector control of induction motor using VHDL which is a standard hardware description language. The vector control algorithm is finally implemented using a simple electronic circuit based on FPGA. The performance of the designed ASIC is verified through simulation and experiment.

Recently effective systemonachip design methodology is developed, and ASIC chip design is much studied for motor control. This paper investigates the design and implementation of ASIC chip for sensorless speed control of induction motor using VHDL which is a standarded hardware description language. The sensorless control strategy is to design an adaptive state observer for flux estimation and to estimate the rotor speed from the estimated rotor flux and stator current. The presented system is implemented using a simple electronic circuit based on FPGA.

This paper proposes the new reducedorder extended Luenberger observer and presents the application to sensorless vector control of induction motor. The main features of the proposed observer are discussed and compared with the other observers.

The BLDCM(Brushless DC motor) has been the Trapezoidal Back Electromotive Force(EMF) due to a surface magnet rotor with nonlinear distribution and fullpitch windings. Theoretically, it should be fed with rectangular phase current in order to minimize torque ripple. But, because voltage source inverter drives BLDCM, perfectly rectangular phase currents are not available. Now in this paper, using fourier series coefficients, calculating the coefficients of harmonic current within available orders and each harmonic component are controlled on stationary frame. Only using four switches, low cost and small size drive can be made and proposed method will be more useful in industrial. Simulation and experimental results prove the validity of the proposed method.

This paper presents the calculation method for the equivalentcircuit parameters and torque characteristics of squirrelcage induction motors. The measurement of motor parameters were calculated by the stator resistance test, the blocked rotor test and no load test to T type equivalentcircuit. Especially, this paper describes the test results obtained by using hall sensor and strain gauge for the current and torque characteristics of induction motors. Threephase squirrelcage induction motor which has 1[hp] was used to the test and the parameters obtained by the test were compared with the maker parameters.

A direct model reference adaptive control (DMRAC) is applied to the speed control of brushless do(BLDC) motor. The main objective is to achieve precise speed control in the face of varying motor parameters and load. The control is described as an outer loop speed control and an inner current loop control which has raster dynamics than the speed loop. The adaptive control is applied to the outer speed control loop. DMRAC is compared to an indirect adaptive controller(IMRAC) and a PI controller. Simulation results show that the two adaptive controllers give similar respose and are superior to the PI controller. However, the DMRAC algorithm is simpler to implement.

An easier implementation method of the field oriented control of induction machine using Matlab/Simulink dSpace board is proposed in this paper. Space Vector PWM and Indirect Fied Oriented Control Algorithm is designed for the help of Simulink. And this system is simultaneously simulated and experimented in Matlab/Simulink environment with dSpace borad (DS1102). It is possible that Matlab and dSpace board compiler can make
$'^*.c'$ and$'^*.obj'$ file of models designed in Matlab/Simulink environment automatically. Experimental results are given. 
Switched Reluctance Motors(SRM) attract much attention in motor because they are reliable and inexpensive. With advance in power electronics and highspeed processors, the performance of SRM has been enhanced greatly But because of its geometric and magnetic structure, the switched reluctance motor naturally creates torque ripples during the commutations of the currents from a supplied phase to an other one. This paper presents the torque ripple reduction using hysteresis current control among of current control techniques.

This paper presents the speed estimation using ANN and the rotor parameter Identification based on the MRAS theory for the sensorless induction motor drives. The motor speed is estimated using ANN model which contains the rotor parameter. And the rotor parameter is identified using MRAS scheme which contains the rotor speed. The rotor speed estimate converges to its actual value as the rotor parameter error converges toward the zero. The simulation using Matlab/Simulink is performed to verify the effectiveness of the proposed scheme.

The equivalent transformation of a brushless DC motor into an separately exited DC motor has been possible with the vector control technique. Vector control is an effective technique for controlling variable speed drives of brushless DC motors. Conventional vector controllers, however, suffer from electrical machine parameter variations because these controllers depend on the parameters. This paper presents the vector control of brushless DC motor using a neural network. In the proposed method, a neural network is employed as online estimator of the nonlinear dynamic equations of brushless DC motor. The neural network based vector controller has the advantage of robustness against machine parameter variations as compared with conventional vector controller The simulation results using Matlab/Simulink verify the useful of the proposed method.

In this paper, For Control of the speed sensorless induction motor propose the method which is controled the motor by operating two axis current in input current of the inverter. This method determines frequency of inverter in order to stator electromotive force and E/F ratio for the setting magnetic flux, drives for speed control using a voltage power converter of the induction motor by means of voltage fed converter with current control ability.

In the industrial motor drive system which is composed of a motor and load connected with a flexible shaft, a torsional vibration is often generated because of the elastic elements in torque transmission. To solve this problem, the twodegreesoffreedom
$H_{\infty}$ controller was designed. But it is difficult to realize that controller. In this paper, a new partial state feedback$H_{\infty}$ controller with resonance ratio control is proposed. Proposed controller has simple structure but satisfies the attenuation of disturbances and vibrations. 
The paper describes a new and rigorous mathematical model for the rotor field oriented system with induction motor which uses the estimated speed and rotor flux based on a Model Reference Adaptive System, as well as the realtime approach. The estimated speed and rotor flux is used for the speed and flux feedback control. The stability and the convergence of the estimator are improved on the basis of hyperstability theory for nonlinear systems. The realtime controller and estimator are implemented with a sampling period of
$926{\mu}s$ using a dual TMS320C44 floatingpoint digital signal processor. The validity of the proposed method is verified by simulation, and also, the sensorless control was tested on the propulsion system simulator, used for the development of Korean HighSpeed Railway Train (KHSRT) [5]. 
This paper describes a downscaled model for a highspeed railway train. The propulsion system of simulator consists of four lineside converters four induction motors driven by two inverters, an eddy current braking system, two dynamic braking systems. The control algorithm of traction and braking including antiskid control can be developed using the simulator. Simulator design procedure. control algorithm and some experimental waveforms are presented in this paper.

In this paper, it presents the design and implementation of a Microstep control IC using Programmable Logic Device(PLD). A Microstep driver is implemented with a 5phase hybrid stepping motor, which has a Pentagon winding, power MOSFETs, and some devices to improve the system characteristics. The Microstep driving method is used for high performance motion control, low vibration and low noise in motor control system. The improvement of the electrical and mechanical driving characteristic of a step motor is achieved by applying microstep driver.

We propose a new method to deal with the optimized autotuning for the PID controller which is used to the processcontrol in various fields. First of all, in this method, initial values are determined by the Switched Reluctance Motor of system and ZieglerNichols method. After deciding binary strings of parents generation using by the fitness values of genetic algorithms, we perform selection, crossover and mutation to generate the descendant generation. The advantage of this method is better than the neural network and multiple regression model method in characteristic of output, and has extent of applying without limit of initial parameters.

Phase angle control ac drives system gains a high popularity due to their simple implementation despite the disadvantage of their poor input power factor especially for large values of phase delay angle. Furthermore it generates subharmononic current at specific phase angle. As input current of do drive systems are sinusoidal, the power factor and subharmonic current characteristics are improve. This paper presents the application of a PWM control technique of do chopper system to reduce the subharmonic current and its characteristics using singlephase dc chopper drive system of universal motor.

This paper presents characteristics calculation method which do not need measurement and test results. This paper draws out every motor parameters for fundamental and harmonic frequencies from the given motor demensions, and presents new equivalent circuits. Using this new equivalent, this paper performs characteristics simulations, and this paper shows that the simulation results agree well with walues obtained obtained by actual load test.

This paper presents a speed control system of induction motor using neural network The speed control of induction motor was designed to NNC(Neural Network Controller) and NNE(Neural Network Estimator) used backpropagation, the NNE was constituted to be get an error value of output of an induction motor and conspire an input/output. NNC is controled to be made the error of reference speed and actual speed decrease, and in order to determine the weighting of NNC can be back propagated through the NNE, and it is adapted to the outside circumstances and system characters with learning ability.

Stratum Axial Type BLDC Motor has remarkable efficiency owing to outstanding characteristics of speed and torque as well as its small size. In this paper 2Degree of Freedom PI (TDOF PI) control method is presented in order to improve the efficiency of Stratum Axial Type BLDC Motor and the simulation proves that the separate control for speed characteristic from answering characteristic of load torque particularly allows the construction of superior control system to PI control system. These results are significant in that the improved Stratum Axial Type BLDC Motor enables the production of much smaller, lighter, and noiseless electric home appliances such as airconditioner and refrigerator.

This paper describes a current fed high frequency resonant inverter used as the power supply for sealingwax. The proposed inverter can reduce switching losses, noise and voltage stress at turnon and turnoff. The analysis of proposed circuit uses normalized parameter and characteristic estimation which is needed in each step before design is generally described according to normalized frequency (
$\mu$ ), coefficient of coupling($\kappa$ ) and all parameters. The theoretical analysis is proved through experiment and this circuit shows that it can be used practically as the power supply system for sealing wax and DCDC converter. 
A half bridge time sharing type high frequency resonant inverter to give VVVF function in the inverter used as power source of induction heating at high frequency is presented in this paper, this paper also realize the output control of independence irrespective of the switching frequency using PhaseShift. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, the principle of basic operation and the its characteristics are estimated by the parameters, such as switching frequency, the variation of phase angle(
${\varphi}$ ) of PhaseShift. It is certain that the proposed circuit will be used and expanded in the high frequency power supplies like induction heating systems. 
A characteristics on the generating Power of a 3Phase Photovoltaic Power system for gridconnectionThis paper was analyzed the highfrequency harmonics, power conversion rate, results of the system's monitor, and measuring data of the system power output of a 3phase photovoltaic power system for gridconnection. The photovoltaic power system consists of a 3phase inverter array, and data acquisition system. The result of an analyzing data of the 50 kW class gridconnected photovoltaic system showed the stable behavior in utilityinteractive operation.

This paper presents a new control strategy of the active power filter to compensate the fundamental and high order reactive power. Using the proposed control strategy, the calculation of active and reactive power of the load is not required. So the system configurations and the controller can be constructed very simply. To decrease the load of active power filter, the LC passive filter bank can be used without any additional strategy. In this paper, the algorithm of the proposed new control strategy is discussed and the experimental results are shown.

Usually, in many applications. high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. And the resonant inverters have to control the output frequency for the reliable operation under the variable load conditions. In this paper, a new switching scheme is proposed as a resonant frequency following control of resonant inverters. With the proposed method. it can be obtained that optimum resonant frequency and unity output displacement factor under the variable resonant frequency adaptively. The detail algorithm of the proposed switching scheme and its characteristics are discussed. And the veridity of the proposed method is confirmed with the experimental results.

In many applications of the bridge type PWM converters as like inverters. AC/DC PWM converters or active power filters, it is necessary to control the input/output current. This paper presents a new current control switching strategy for the bridge type PWM converters. And variable speed motor control applications fed by current controlled inverter, PWM AC/DC converter applications. active power filter applications and classD amplifier applications using the proposed new current control switching method are shown.

This paper presents a high powerhybrid multilevel PWM rectifier with unity power factor. The features and advantages of the proposed PWM rectifier can be summarized as follows; 1) It realizes the high power high voltage AC/DC power conversion. 2) It uses no transformer which is bulky and heavy, 3) It has hybrid structure so that switching devices can be effectively utilized, 4) It produces high quality AC current even in high power high voltage applications, 5) The input power factor remains unity by simple modulation index control. The multilevel rectifier is analyzed by using the circuit DQ transformation whereby the characteristics and control equations are obtained.

전동기의 속도 및 토크제어 운전시 인버터 제어 방식으로서 최대 효과적인 전력을 사용할 수 있으며 저차 고조파를 저감시키는데 효율적인 스위칭방식으로 공간전압벡터 변조(SVPWM)를 사용하고 있다. 따라서 많은 논문들이 SVPWM의 방식을 이용한 시뮬레이션을 하게 되는데, 본 논문에서는 최근 시뮬레이션에 많이 사용되고 있는 Matlab/Simulink를 이용하여 SVPWM 인버터를 구현, 이를 유도전동기 구동시스템에 적용하여 속도 및 토오크 응답, 상전류 파형을 시뮬레이션 결과를 제시하여 본 논문에서 제안한 SVPWM 인버터의 블록 모델의 유효성을 보이고 있다.

In conventional zerocurrentswitching(ZCS) PWM converters, the switching loss, stress and noise can't be minimized because they adopt auxiliary switches operated in hardswitching. In this paper, new ZCSPWM converters of which auxiliary switches always operate with softswitching are proposed. Therefore, the proposed ZCSPWM converters are most suitable for systems requiring highpower density. The characteristics of these converters are verified by results of simulation.

In this paper, a new approach for digital feedback control of PWM inverter is proposed, in which an output DB(DeadBeat) control is achieved combined with a simple disturbance observer. The deadbeat controller, which is constructed multiple loop control scheme for PWM inverter, is used for fast transient response. The disturbance observer can make the disturbances be cancelled by adding feedforward compensating loop in controller. The simulation result show the proposed control scheme can achieved good voltage regulation against large load variations.

This paper proposes a harmonics reducing circuit for fluorescent lamp inverters using hybrid type smoothing circuit with pumping and smoothing capacitors. A waveform of fullwave rectification used as a direct current power supply at fluorescent lamp inverters contains a lot of harmonic wave from inrush current which is generated near the maximum of input voltage with purse shape when voltage smoothing capacitor is charged. Therefore, in order to suppress inrush current which will result in harmonic wave. this paper proposes a method to control abrupt charging current by use of charging voltage at pumping capacitor. The suppression of harmonics generation at lamp current is confirmed through simulations.

Germicidal lamps efficiently emit a large amount of ultraviolet rays 253.7nm which have excellent germicidal effect. The lamps are primarily useful for sterilization of air, the surface of various materials and water or liquid. In this paper, analysis of the charge pump power factor correction inverter for driving a 65W UV lamp and electrical characteristics of the lamp are discussed. The operation of the inverter circuit. in which the lamp is included as a load, is analyzed. Experimental results of the inverter circuit are also presented.

The Static var compensators(SVC) are intensively studied to realize high performance power equipment for electric power systems. Rapid and continuous reactive compensation by the SVC contributes to voltage stabilization, power oscillation damping, overvoltage suppression, minimization of transmission losses and so on. In this paper, instantaneous power vector theory which can expresses the instantaneous apparent power vector is proposed to control reactive power. The validity of the proposed method is confirmed by simulation studies.

Hwang, LakHoon;Cho, MoonTaek;Lee, SangYong;Ryoo, JuHyun;Kim, JuRae;Kim, JongSun;Yoo, ChungSik 1209
This paper presents a PSPICE circuit model for the simulation of both static and dynamic characteristics of fluorescent lamps. The model can by utilized for an electric ballast simulation with continuous dimming and transient mode simulation such as step dimming Characteristics of a Rosentype piezoelectric transformer were analyzed by combining an equivalent circuit with piezoelectric equations and the relation between the characteristics and the dimension of the PT was studied. 
A new softswitching PFCInverter for Induction Motor's operation with single phase or three phase medium size is proposed. In order to improve the power factor and the efficiency, in this paper, the ZVT topology in the conventional PFCInverter is adopted. So, the operation mode of the proposed ZVT PFCinverter is analyzed and the optimum circuit is designed. At last, the PSPICE simulation and experiment results are presented in order to verify the validity of the proposed circuit.

For the application of softswitching technique to single Phasefull bridge inverter. in this paper ZCT(Zero Current Transition) and ZVT(Zero Voltage Transition) techniques proposed previously are compared and discussed the merit and demerit of both. Both have a excellency that can reduce the number of auxiliary switch and resonant circuit compared to other techniques and achive softswitching in auxiliary switch itself. Therefore, it has enabled us to have benifits of realizing high efficiency and reliability, low EMI for high switching frequency and reducing the cost as well as size of device.

A new control technique is proposed to reduce the distortion of UPS output voltage. The Load of UPS is rectifier which has many harmonics on its output current in many cases. The distortion of output voltage by the harmonics is repeated at the same position in one cycle. Therefore we can assume that the next cycle wave form would be similar to the previous one. The repeated error can be estimated and be compensated by the Multi controller at every sampling times.

TFM(Transeverse Flux Motor) is a switched reluctance motor with a new structure of novel design concept based on the high efficiency and power density compare to induction motor used on wide industrial field. To apply TFM to various industrial field instead of induction motor, an efficient converter drive system for speed and current control in TFM is required. This paper realized PWM asymmetric converter drive control system for TFM using IGBT and DSP. To certificate the high power and efficiency drive characteristics of realized PWM converter drive control system. simulation was excecuted on speed command and load variation using Matlab/Simulink.

In this paper, load paralleled type FB series resonant inverter of a new novel type is proposed. In the output control method, phaseshift driving signal control method with CVCF introduces. Also by driving signal patterns, the operation principle of the proposed circuit in detail is described and its characteristics are compared on separated ratio(n). According to each the mode in order to the analysis and characteristic evaluation of the circuit state equations are derived and presented using normalized parameter. To verify the theoretical analysis result, experimental results are provided.

The output voltage of UPS must not vary according to the load variation But the output voltage varies due to the load variation when a PI voltage regulator is used which has inherently a static state error. This paper presents a staticerrorfree digital PID voltage regulator for an UPS inverter to overcome additionally the voltage unbalance problem in three Phase system as well as the above problem.

To reduce harmonics in the AC line and achieve a unit power factor, A 4 paralled single phase PWM AC/DC converter has been proposed. In this paper, the coupling components are derived analytically from PWM converter input transformer model and control scheme to solve this problem is proposed. Unit power factor was obtained and the ACside current harmonics were reduced. Simulation results show the usefulness of the proposed method and applicability to PWM converter in auxiliary block of high speed train.

A new control method of three phase converter without measuring input phasevoltage and DClink voltage is proposed. Input phasevoltage of these required voltages is estimated using EKF(Extended Kalman Filter) and DClink voltage is estimated from the measured line currents and the estimated input phasevoltage. This control method is achieved without PLL(Phase Locked Loop) which senses the angle of input phasevoltage and DClink voltage sensor. In addition, the proposed method controls high power factor and DClink voltage utilizing the estimated phase angle. This paper describes the effectiveness of the proposed estimated algorithm through simulations.

This paper considers the problem of eliminating harmonics in the inverter output waveforms. The approach is based on the minimization of the current harmonics in the induction motor by space vector modulation method. Reference voltage is compensated with injection of controlled current harmonics which are calculated to reduce current harmonics through sampled current harmonic analyzing algorithm. The theoretical analysis is carried out using computer simulation. It is verified that proposed SVM technique could reduce current harmonic component and improve THD.

This paper discussed for hal·monic analysis in AC electric arc furnace. The arc furnace system is designed by a harmonic current source with considering voltage stabilizer. In this paper, an adequate example is shown for the IEEE harmonic limits when a tuned filter is installed. The simulation established by HI_WAVE of SKM.

A new control method using average comparison strategy have been proposed in this paper. This control method realizes sinusoidal input and output current. unity input displacement factor regardless of load power factor. Moreover, compensation of the asymmetrical and/or harmonic containing input voltage is automatically realized, and calculation time of control function is reduced.

본 논문은 부하가 불평형인 경우에 능동필터의 제어를 수행하였다. 불평형 부하는 역상분 전류성분을 발생시키고 이것은 인버터의 직류단에 120Hz 전압리플을 발생시키게 된다. 그리고 인버터가 역상분까지 보상하게 되므로 전력용 반도체의 정격용량이 커져야 하는 문제점을 발생시킨다. 이런 문제를 해결하기 위해 동기좌표계에서 역상분 성분의 분리를 수행하였고, 이 성분을 전원측으로 흐르게 제어를 하였다. 이것의 타당성은 실험을 통해 검증되었다. 실험은 10kVA 정격의 병력형 능동필터로 구현되었다.

The aim of this paper is to present a review of recently used current control technique for threephase voltage source pulsewidth modulated converters. Various technique, different in concept, three current control methods are presented in this paper. Current control methods to be applied in system are PI controller. Predictive current controller. Minimumtime current controller respectively. In initial state and transient state, the response characteristics of three current control methods are verified through simulations.

This paper describes control of water pumping system using PV array. An integral part of the system with various system components be constructed PV array. maximum power point tracker BLDC motor and pump. BLDC motor has the quality of torque output and efficiency, has been more widely used in a field for multifarious application. However pumping system using PV array has limited for application because output characteristics of solar cell are greatly fluctuate on the variations of insolation, temperature and loads. For this reson, in this paper each parts efficiently contoroled by the maximum power point tracker, the vector control method of BLDC motor and the pressure PI controller using TMS320C 31.

In this paper, a control scheme for induction heating is proposed. The propose scheme estimates, resonant frequency by PI control subbing a phase of output voltage and resonant capacitor voltage. There are would be two advantages in the proposed system over existing induction heating system. One is the rapid resonant frequency estimation. A other is the just control of temperature. Power Circuit is used a inverter stack and transformer rated on 5.5kw.

직접토크제어(DTC)가 빠른 포크 응답을 가지고있다는 것은 널리 알려진 사실이다. 이것은 기존의 벡터 제어와는 달리 공간 전압벡터에 의해 직접적으로 토크와 자속이 제어되기 때문이다. 이로 인해 직접토크제어 기법은 그것이 도입되어진 1980년대 중반 이래로 노크의 빠른 응답을 필요로 하는 분야에 점차적으로 적용되어져 왔다. 하지만 이런 장점에도 불구하고 직접토크제어는 히스테리시스 밴드, 속도 그리고 전동기 파라메타의 변화에 따른 스위칭 주파수의 변화와 토크 리플의 증가, 좋은 성능을 위한 높은 제어 주기 등의 몇 가지 단점을 가지고 있었다. 그래서 DTC의 단점들을 해결하기 위해 여러 연구들이 이루어져 왔다. 본 논문에서는 이들 단점들 중 하나인 토크리플을 개선하려한다. 다른 논문들에서도 일정 주파수를 가지는 여러 제어 기법을 사용하여 직접토크제어의 단점을 해결하려 했지만 너무 복잡하고 큰 성능을 나타내지 못했으며 몇몇 논문들은 오히려 직접토크제어의 장점인 빠른 응답성을 잃는 결과도 가져왔다. 그래서 본 논문은 간단한 개념을 가지고 토크리플을 줄이며 일정 스위칭 주파수를 가지므로 DSP를 사용하여 제어하기 용이한 직접토크제어기법을 제안하려 한다.

Vector control of a single phase induction machine(SPIM) is usually employed by mechanical methods than electrical ones. The disadvantage of a SPIM has large noise at the starting. Using auxiliary winding which is only utilized for starting, the SPIM can be controlled with the vector control method. Regarding a auxiliary winding one phase, the SPIM is analyzed by the unsymmetrical two phase motor and phase transformation is unnecessary such as three phase IM. Including a auxiliary winding, SPIM is modeled by mathematical getting by component of turns ratio with main to auxiliary winding. It will be take with complicated resultant formula, by comparison to symmetrical three phase TM. For using the vector control theory, it must be decoupled of rotor flux and torque component. stator current is controlled and decoupled. This paper presents a variablespeed control system of SPIM, which to decoupled with flux and torque component and to use machine equivalent circuit referred to rotor, conventionally three phase IM by similar method.

본 논문에서 비교하는 두 시스템은 모두 전력계통에서 발생할 수 있는 고조파 전류를 효과적으로 보상할 수 있는 시스템이다. 전력계통에서 고조파전류는 계통전압에 장해를 주기 때문에, 프릿카나 각종 전력용기기의 발열 진동, 소음 혹은 유도잡음 장해등의 원인이 된다. 따라서, 이에 대한 대책이 중요한 문제가 되고 있다. 본 논문은 이러한 고조파보상 시스템의 새로운 형태로써, 플라이휠에 의해서 만들어지는 에너지 저장시스템에, 전압형 PWM 인버터를 병용하여 순시제어가 가능한 시스템을 설계하는 것이다. 그리고 여기에 사용되는 회전기로 각각 권선형과 농형을 사용하여 시스템을 구성하고 그 특징과 장/단점을 비교 분석하였다.

New switching signal pattern for four switches is proposed to prevent the shortage of PWM ac choppers. In the proposed technique, four signals to four power switches are generated without current transformer, while the conventional technique requires sensing the polarity of input voltage by voltage comparator and checking the direction of input current by the current transformer. The signal circuit built by the proposed technique is simple, and reduces also the switching loss.

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter is proposed. The new converter improves the drawbacks of the previously proposed ZVZCS FB PWM converters [15]. A simple auxiliary circuit with neither lossy components nor active switches achieves ZVZCS of the primary switches. Since the proposed converter has many advantages such as simple auxiliary circuit, high efficiency, and low voltage stress of the rectifier diode, it is very attractive for the high power applications. The principles of operation and design considerations are presented. The experimental verifications from 2.5kW prototype converter operating at 70kHz are presented.

크로징 스위치인 아바란치 트랜지스터를 사용하여 수 나노
$\sim$ 수십 나노초의 고전압 펄스를 만들 수 있다. 반도체소자의 발전으로 인하여 빠른 회복시간을 갖는 소자가 개발되어 다이오드를 이용한 오프닝 스위치로도 수 나노$\sim$ 수십 나노초의 고전압 펄스를 얻을 수 있게 되었다. 본 논문에서는 전자총 그리드 펄서를 개발하기 위하여 자기스위치를 사용한 펄스압축기술(MPC : magnetic pulse compression)과 SOS (semiconductor opening switch)다이오드를 이용한 펄스 발생기에 관한 연구를 수행하였고 실험결과로$50{\Omega}$ 부하에 대하여 3 kV, 26 nsec 펄스를 얻었다. 
통신용 전원시설의 고장은 거의 모든 통신서비스의 중단을 일으킬 수 있기 때문에 통신용 전일시설의 신뢰성은 매우 중요하다. 그 중 통신시스템에 직류 전원을 직접 공급하는 정류시스템은 가장 중요한 전원시스템으로 분류될 수 있다. 현재 여러 전화국 및 무인국사에서 운용되는 정류시스템은 전원관리시스템에 의해 실선으로 감시되고 있으나 중단없는 서비스제공을 위해서는 전원관리시스템과 통신을 통해 효율적으로 감시 및 제어가 이루어져야 한다. 따라서 한국통신에서는 이러한 요구에 부응하기 위하여 소형, 경량화 및 자연냉각방식등을 채택하여 운용유지보수 효율이 향상되고, 전원관리 시스템이 통신을 통해 시스템 감시 및 제어가 가능한 신형 정류기 개발을 완료하였다.

본 연구에서는 마이크로프로세서를 이용하여 경제적인 하드웨어의 구성과 다양한 소프트웨어 알고리즘을 구현함으로서 기존의 아날로그방식이 아닌 디지털 신호처리를 이용하여 가변 주파수에 의한 휘도 조절로 음향 동기화조명제어가 가능한 네온관 조명장치 컨트롤러를 개발하였다.

고 주파수 스위칭 동작을 하는 DC/DC 컨버터 혹은 인버터를 효율적으로 제작하기 위하여 고주파용 펄스 변압기의 역할은 매우 중요하다. 동작주파수가 수십 혹은 수백 kHz일 경우에는 최소의 부피로 충분한 전력을 수용하면서 변압기를 설계 및 제작하기 위하여 코어 및 권선의 선정, 코어 및 권선의 손실, 변압기의 온도상승요소, 변압기의 발열, 변압기의 누설 인덕턴스, 권선 케페시턴스, 분포 케페시턴스 그리고 공진주파수 등을 고려하여 설계하고 시험 평가하여야 한다. 본 논문에서는 위의 여러가지 요소들을 고려하여 동작주파수가 100kHz인 DC/DC 컨버터 혹은 인버터를 고밀도 제작하기 위하여 고주파용 펄스변압기를 최소의 부피로 수kW 용량으로 변압기의 온도상승요소를 고려하여 설계, 제작 그리고 실험한 결과에 대하여 기술 하고자 한다.

Commutation failure can be considered as the severest abnormal operation of thyristor HVDC converter. During the failure, power conversion from DC to AC is stopped until the AC voltage get recovered. The process of thyristor converter is subscribed at normal and abnormal state, respectively. The detection and the protection for Cheju HVDC are explained by computer simulation results.

The operation of BackToBack HVDC system for asynchronous connection is described. It can exchange electric power up to 300 MW between separately operated two rower systems, making the interaction on each system minimum. The analysis is done under three different AC transmission lines interconnected to BTB HVDC.

In this paper, we proposed a new singlestage singleswitch power factor correction(S4 PFC) converter with output electrical isolation. The configuration of this converter is achieved by combining a fly back circuit and a forward circuit in one power stage. To verify the theoretical analysis of the proposed converter, a design example is given with its Pspice simulation and experimental results.

A single stage AC/DC converter based on a full bridge topology suitable for high frequency soft switching converter applications is proposed. The proposed converter has high power factor, zero voltage switching, low noise and high efficiency. A pulse width modulation control is employed to reduce the switching and rectification losses respectively. This proposal converter has simple structure and low cost, The modelling and detailed analysis are performed to derive the design equations, a prototype converter has been designed and experimented. The new converter is attractive for highvoltage, highpower applications where IGBT's are predominantly used as the power switches. The principle of operation, features, and design are verified on a 1.5kW, 30kHz, IGBT based experimental circuit.

In the charge system, a contact typeconvenientcharging method is insufficient because of the contact failure around moist environment and troublesome question to put in and pull out. For the solution of this problem, an electromagnetically coupled noncontact charger for the rechargeable cell is proposed using ZVS multiresonant forward converter. In this paper magnetizing inductance, leakage inductance and coupling coefficient, k are observed. By using the obserbed value, the proposed circuit is simulated by the PSPICE and implemented and the peak voltage of switch and output power are measured.

A zero voltage and zero current switching(ZVZCS) fullbridge (FB) PWM converter with secondary auxiliary circuit is proposed. Based on the ZVZCS technique, the ZCS of the laggingleg switch and ZVS of the leadingleg switch are implemented. And the each secondary side voltage overshoot is decreased by additional secondary auxiliary circuit in this paper. The illustration of its operation principle and the simulation result are presented here.

A new ZVT PFC for using 3[KW] power amplifier is proposed. Generally, the single phase diode rectifier has been widely used in the SMPS of the conventional power amplifier. But this rectifier has occurred some problems which are the input power factor and current harmonics. To solve the above problems, in this paper, two topology is adopted. The one is the boost type PFC for improving the input power factor. The other is the ZVT resonant circuit for reducing the switching loss and stress. In this paper, the proposed topology is analyze designed to built the ZVT PFC for using 3[KW] power amplifier. In order to verify the circuit va finally, the PSPICE simulation and experiment results are presented.

본 논문에서는 입력부, 특고압 발생부 및 고압 정류부, IGBT Pulse Switch로 구성된 Gyroklystron용 대전력, 고전압, 전류 펄스 전원장치의 설계 및 개발에 대하여 기술하였다. 대전력, 고전압, 전류 펄스 전원장치를 위한 각 구성부분의 제어 및 설계 특징은 다음과 같다. 입력부인 IGBT Inverter는 펄스 전원장치의 전압 제어를 위하여 출력 고전압을 Feedback System 제어에 의해 Pulse 설정 전압을 갖도록 제어하며, 또한 Pulse 출력중에 직류 고전압부의 전압강하, 즉 Pulse 전압의 Drop이 커지는 것을 방지하기 위하여 Fast Dynamics를 갖도록 Feedback System을 구성하였다. 3대의 단상 특고압 승압변압기가 직렬로 구성된 특고압 발생부는 PWM된 전압을 입력받아 특고압으로 승압시킨다. 특고압 변압기는 고압 Pulse성 전압과 매우 높은 dV/dt 전압이 인가되므로 Stray Capacitance가 최소가 되어야 하며 절연파괴로부터 보호될 수 있어야 한다. 고압 정류부는 Inverter와 특고압변압기에 의하여 전원이 공급되므로 교류전압의 교번순간에 매우 높은 전압 변동률을 가지는 Fast Recovery High Voltage Rectifier로 설계, 제작되어졌다. Pulse Switch인 IGBT Switch는 Gate Driver에 의해 구동되어 진다. 주어진 Pulse 사양을 만족시키며 특히 소자의 전압 특성을 고려하여 120KV의 전압값을 갖도록 설계, 제작하였다. 본 논문에서는 고전압 펄스 전원장치 각 부분의 설계에 대하여 기본적인 사항들을 제시하며, 실험결과를 통하여 제안된 방식의 우수한 특성을 입증한다.

In this paper, voltage control APF(Active Power Filter) is introduced to improve power factor and reduce harmonic, generated from nonlinear load. The voltage controlled APF which is consisted of inverter and passive filter operates with nonlinear load simultaneously. According to the results of simulation, it is proved that the proposed system has the performance of improving power factor and reducing harmonics.

In this paper, a solution of remote manager system for power plant was introduced. In conventional remote control system computer or adapter are need to communicate with manager computer. As the number of managed power installations increases, the remote management system is going to be complicated and expensive. To solve the problem, a Multifunctional Board for power plant is developed. The Multifunctional Board has a both function of remote management and communication in LAN. This system will be hope to decrease the cost of remote management.

In this paper, DC/DC converter has been composed of a capacitor which has not only a source division function but a resonant function instead of a previous source division capacitor. In addition to the proposed circuit is introduced a soft switching technique (ZVS). The proposed paper certified that theoretical waveforms are equal to experiment waveforms of power, output voltage, voltage ripple etc. and to be possible to control using division ratio.

Sigmadelta modulation can perform A/D conversion with a highresolution. It is useful for simplifing the system and spreading out inband signal noise. When the sigmadelta modulation is applied to a switching converter, it can suppress the harmonic frequencies of output signal and be realized with a simple structure. In this paper, some methods of sigmadelta modulation are discussed so as to find the suitable structure for a switching converter. Noise characteristics are calculated and analyzed through simulations.

This paper proposes a CurrentFed Push Pull type DCDC converter using LCCC Resonant circuit and Zero Voltage Switching function to reduce turn on and off loss at the switching instants. This paper have the advantage which is able to operating safely in load short, because of DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC Power supply. The capacitor (
$C_1$ ,$C_2$ ) connected in switch are common using as resonance capacitor and ZVS capacitor. The analysis of the proposed CurrentFed Push Pull type DCDC converter is generally described by using normalized parameter, and we have evaluated characteristic values which is needed to design a circuit. We confirm a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices. 
The thyristor among the powersemiconductor elements, which has large current capacity and high voltage, is used widely nowadays. When the thyristor was being used to the long time, this element may be able to arise the system trip caused by changing the characteristic and dropping the performance. Therefore, it would be necessary to analyze the characteristic of element to maintain the stable operation of the system. In oder to analyze this characteristic, it would be need to test forward direction, reverse direction and leakage current by supplying the halfsine wave voltage. Among these testing, transient current condition is generated from the testing of leakage current. This transient current may be the main factor of the error in the precise measurement of leakage current. Therefore, this paper analyzes the relationship between supply voltage and transient current in measuring leakage current of the SCR, and then suggests the condition and cause of transient current as appearing the leakage current in the testing the leakage current.

In general, the expected life of power semiconductor elements is known for semipermanent, but actual characteristics are changed according to the such environment conditions obviously because of using time or operating condition. Specially, in case of using at the power plant it is very important to sustain reliability for power semiconductor which it affect to stop operating condition as deterioration or break. Therefore, we need to apply maintenance technics to got the reliability which is a prediction method of life cycle. This paper shows the result of the analyzed data for element characteristic and effects used practically and we had developed the effective equipment which for diagnostic the semiconductor performance.

In order to turn on the SCR gate, trigger signal source have to provide appropriate gate current and voltage under the gate rating based on the characteristic of SCR, the nature of load and power. It will be essential design factors such as trigger source impedance, trigger signal occurring, signal time width and turn off conditions. Also minimum gate trigger current is changed with the deterioration of SCR. SCR, which is needed large gate trigger current absolutely, is very important for SCR characteristic test because it causes unstable output in the misfile or makes a trouble to pulse trigger circuits. This paper shows scheme to test the performance of SCR with the precision analyzing mechanism and the changing trend of minimum gate current under the trigger conditions.

This paper proposed the single phase multilevel PWM AC/DC converter using binary combine which controls input current by combining buck converters to improve input current characteristic, and confirmed its validity throughout simulation and experiment. This method, which is multiplying and duplicating output of converter of equal capacity, has the advantage of being able to control unit power factor of input current and reducing of the problem caused by high frequency switching, and appling to high power converter because filter is not necessary etc.

This paper presents a new PWM DC/DC converter with multioutput using single secondary winding, which has two output characteristics of the isolation and nonisolation simultaneously. The proposed converter topology is consisted of the only one switch and single secondary winding. The proposed converter, therefore, has advantages not only low cost but also high power density. Operating principal of the proposed converter topology with conventional ZVT (ZeroVoltageTransition) is illustrated in detail and the validity of the converter is verified with several interesting simulation results.

This paper presents a microcontrollerbased control circuit for color variation of high brightness RGB LEDs in
$8{\times}8$ matrix array. The control circuit is comprised of an AT89C52 chip, D Flipflops, and transistors for switching, and is used to adjust the number of LEDs operated for color variation. For a stable operation, it is required that the input current to each LED should be maintained to a normal value irrespective of the number of LEDs operated. 
This paper presents a new method to reducing inrush current and energy saving of capacitor starting singlephase induction motor used in airconditioner. It can be obtained that proposed system is low cost and small size as compared with other controller. Experiments are focused on a capacitor starting singlephase induction motor. The optimal power saving and inrush current limiting by phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

Zerovoltage and zerocurrent switched singlestage approach with high power factor is presented to reduce the switching losses and to achieve sinusoidal, unity power factor input currents. This singlestage approach, which combines a boost converter used as PFC with a halfbridge converter used as do to do conversion into one power stage, has a simple structure and low cost. At the same time, since the switches of the proposed converter are designed to be turned on at zerovoltage and off at zerocurrent, the switching losses could be reduced considerably. Detailed analysis and experimental results are presented on the proposed converter, which is operated at constant switching frequency and in discontinuous conduction mode.

In this paper, it is proposed to constant power control of solar power system. The solar power system has disadvantage that low power density and variable power output. Proposed strategy is controled by DC/DC converter using phase shift PWM and IPD type control applying type 1 digital system. The validity of proposed control strategy is verified from simulations results using PSIM.

This paper deals with a 300kV dc charging system to be used ?s a voltage source in a circuit breaker synthetic shortcircuittest facility. Cockcroftwalton circuit is used to step up the rectified voltage from a single phase transformer of which primary winding is hooked up to an ac220 wall plug. Two systems with the same ratings have been designed and manufactured. The two system have been made of different supporting structure with different insulating materials. The paper describes a couple of charging schemes, system configurations and the synthetic test circuit in which the developed system is to be used.

고속철도는 상당히 복잡한 시스템이기 때문에 적절한 시스템엔지니어링 도구의 사용 없이는 추적관리에 드는 인적비용 및 시간이 만만치 않으며 오류가 생기기 쉽고 매우 비효율적이다. 따라서, 시스템 요건에 정의된 목표 성능을 달성하고 시스템간의 불일치를 최소로 하기 위해 체계적인 시스템 통합 절차를 제공할 수 있는 시스템 엔지니어링 데이터베이스 구축이 필요하다. 이 데이터베이스는 시스템 요건부터 시스템 기능, 컴포넌트, 평가 요건, 평가 결과까지 추적성을 갖도록 구축되어서 연계 관리를 가능하게 한다.

This paper presents the control algorithm verification process for VCB (Vacuum Circuit Breaker) of Korean High Speed Train. In order to enhance the reliability of the control algorithm, the verification process must be performed. The verification is conducted by comparing the predesigned control algorithm with the preplanned scenario by simulation tools such as SDL and MSC. This verification process will be applied to the other control algorithms of various control units of Korean High Speed Train.

In electric railway system, potential of rail has been risen, for returncurrent flows through rail. The magnitude of rising voltage is different to railway feed system, ground admittance of rail and the load current. If rising voltage of rail is large, electric shock can be occurred to passengers and maintenanceworker. In this paper, we estimate the rising voltage of rail in high speed railway system and check the safety to human beings.

The automotive environment presents to the FMCW radar sensor a multitude of moving and fixed targets and the sensor must detect and track only the targets which may pose a threat of collision or passengers accident. The sensor must function accurately in the presence of background echoes generated by moving and fixed targets, ground reflections, atmospheric noises, including rains, fog, and, snow and noise generated within the receiver. False detection of the desired target in this environment may issue false alarms. That may be dangerous to the passenger and the vehicle. A high false alarm rate is totally unacceptable. The false alarm mechanism consists of noise peaks, crossing the threshold and the undesired response of the system to off lane targets which are not potentially hazardous to the radar equipped vehicle. This paper presents an improve technique safety performance for driverless operation using FMCW radar sensors.

In this paper, the complex accelerating degradation of traction motor driven with VVVF controlled inverter were performed on the form coil samples with the 200 Class insulation system. in order to evaluate the reliability and the longterm life. After aging, the dielectric and PD properties were investigated on the 10 cycles aging sample in the range of
$20{\sim}160[^{\circ}C]$ and AC$250{\sim}2250[V]$ to diagnosis the condition of endlife and find the dominative factors of degradation. 
In this paper, sample coils for stator formwound winding of traction motor were tested by the accelerative thermal degradation, which composed of heat, vibration, moisture and overvoltage applying. Reliability and expected life were evaluated on the insulation system for 200 class traction motor. After aging of 10 cycles, insulation resistance and PI properties were investigated as diagnosis tests in the range of
$20{\sim}160^{\circ}C$ . Analysis of polarization properties was performed on the base of do currenttime change. 
Bae, BonHo;Sul, SeungKi;Kim, SangHoon;Lee, IlHo;Jung, EunSung;Lee, InSeok;Han, SungSoo 1377
본 논문은 산업자원부 중기거점기술개발사업의 일환인 '전동차 추진장치 기술 개발 과제'로 개발된 전동차 구동 시스템에 대하여 서술하고 있다. 개발된 전동차 구동 시스템은 4대의 210kW 유도전동기를 병렬로 구동하며 주 전력 소자로 IGBT(Insulated Gate Bipolar Transisotr)를 사용하여 스너버 회로가 없는 간단하고 신뢰성 있는 시스템을 구현하였다. 제어 기법으로는 벡터 제어 기법을 적용하여 저속 기동 및 가속시의 토오크 제어 특성을 향상시켰다. 본 논문에서는 전체시스템의 구성 및 특성을 약술하고, 적용된 벡터제어에 대하여 논하였다. 그리고 본 과제를 위해 새로 제작된 전동차 1편성을 이용하여 한국철도차량주식회사 상주공장의 시험 전차선에서 주행 시험을 실시한 결과 개발된 전동차 구동 시스템의 성능이 목표 사양을 만족함을 확인하였다. 
A multitrain operation simulation software is under development, in this G7 Project for a High Speed Train System, to simulate the running performance, power consumption, signalling and operation. In the first stage, a Train Performance Simulation (TPS) software is introduced in this paper. This is a core module of whole system and gives some parameters of a train, e.g., its position, speed traction and braking power and electric power system state, etc. In this paper, calculation technique was used for voltage drop at the train's positions and major posts along the catenary line. The final program will be used as an evaluation tool for system performance in constructing a new line or introducing a new train system.

To determine operational requirement, the environmental condition for an equipment must be investigated, and to certify equipment's normalized operation, appropriate test must be carried out under the considered environmental condition. The actual environmental conditions to which equipment is likely to be exposed are normally complex and will comprise a number of environmental factors and corresponding parameters, When defining the environmental conditions for a certain application it is, therefore, necessary to list the factors involved and select the appropriate severity. The operational environment is structured in two separate such as requirements, guidance and test specifications. For the preparation to determine operational requirement, operational environment of railway signalling equipment is investigated.

Railway signalling system is required to be high safety against collision, derailment and collision at level crossing and to be high availability. The signalling system is usually divided into automatic train control, interlocking and centralized traffic control systems and each system must be high fail safe and availability. This study focused on reliability calculation of vital systems in train control system.

In this paper, a numerical calculation method based on CSM has been described. The electric field must be nonuniform even close to railway feed system. In that case, to calculate induced voltage, this paper uses the mutual capacitances between a conductor and railway feed system. The induced voltages of a conductor located at point (height=4m, distance=8m) near by railway feed system are calculated from 370V to 668V.

본 논문에서는 최근 선진국에서 활발히 연구되는 EMF 차폐 대책의 일환인 수동루프에 대한 이론적 분석 방법을 제시하고, 고속철도 급전선 주변에서의 자계 저감효과를 보이고자 한다. 그 결과 수동루프를 이용하여 자계 저감효과를 확실하게 나타낼 수 있었다.

국내에서 운용중인 단권변압기를 사용한 단권변압기(AutoTransformer) 급전계통이 철도청의 경우 상하선을 전기적으로 구분하여 사용하고 있는 반면, 건설중인 고속철도의 경우 상하선을 병렬연결하고 있어 이에 대한 시뮬레이션을 수행하여 전기적인 장단점을 확인하여 향후 급전계통 방식을 선정하는데 기본 안을 제시한다.

This paper presents a novel simulation of dynamic voltages in ATfed railway power supply. Proposed algorithm is efficient and simple by using the circuit decoupling and iteration method. To verify the proposed method, we used real condition operating data and performed a several case studies. Under train is constant power, we separated each AT section to calculate a loop current, train voltage on any position. Finally, this result utilizes a planning and operation of electrical railway systems.

The electrified railway has various power supply schemes. Although the identical trains are operated in same condition and the impedance of track are equal, the genealogy impedance of track is changed according to composition method of feeding scheme. So, the harmonic current flowing into the railway substation are greatly unlike. For simulation of harmonic magnification flowing into the railway substation according to feeding scheme, we propose 6port network analysis method based on 4port network, find 6port equivalent model of each circuit component, and compare and investigate harmonic magnification in the case of parallel post and normal feeding scheme.

This paper is on optimal design for DC substation capacity for Mass Transit System. Three factors are considered for the design i.e. substation arrangements, line configuration and substation power capacity. In this study, we discussed substation power capacity only. At first, DCfedtraction system is introduced on an outline, a characteristics of train and fed network. Optimal design procedures is described, and modelling for DCfedtraction system are presented. The circuitsolution method is presented by matrix formula. In order to simulate DC substation power capacity more closely to actual situations, we proposed the program.

The regulation performances needs high control gain in novel output feedback controller but high control gain is decreased relative stability of the total system. Thus, this paper proposed neural network controller(NNC) for output feedback controller. In this scheme, output feedback controller are guarantee global stability and NNC are controller steadystate error and defined optimal control law. And we demonstrated this scheme by simulations.

Distubance of airgap sensors by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension (EMS) systems. Thus, this paper proposes the output feedback controller with discrete kalman filter for the EMS systems. The discrete kalman filter estimate true state value and output feedback controller guarantee stability. The benefit of this scheme are shown by simulation. Therefore airgap disturbance are rejected successfully.

In the future light rail vehicle is more attractive than subway, because of construction time and cost. For light rail vehicle are two types of traction motors. one is traditional rotating type and the other is linear motor. Linear motor is not better in consideration of efficiency and power factor than rotating type. But the motor needs no translation equipment for linear motion and with them can be constructed low floor vehicle. In this paper will be designed a linear induction motor with consideration of operational condition and analysed operating characteristics using FEM program and equivalent circuit.

철도에서 사용하는 무선통신망은 열차의 안전운행을 지원하는 보조적인 장치로 선로변의 상태, 열차내의 응급상황 및 긴급지시상황 등을 열차간 또는 열차와 역기지국간에 정보를 교환함으로서 열차의 안전운행을 지원하고 있다. 또한, 통신방식은 VHF대역의 아날로그방식을 채택하여 동시에 여러 사용자가 동일 주파수로 통화를 할 수 있으나, 인접지역과의 간섭 및 혼신이 발생할 수 있어 통화품질이 저하될 수 있다. 본 연구에서는 기존철도에서 사용하는 무선통신망의 운용방법과 주파수대역, 송, 수신출력 및 사용 안테나 특성 등을 조사하였으며 이를 토대로 수도권 구간의 9개 역기지국에서의 통화권에 대해 Cell Planning을 통한 통화권분석을 하였다.

The railway signaling system consists of microcomputerized vital devices on board and ground, which are connected to one another by track circuits, and interlocking equipment for route control. Therefore it is important to validate the required functions of developed system and interface between developed signaling systems. To verify the conditions and functions of signaling functions, the laboratory prototype test bench, which consists of personal computers LAN, will be developed. In this paper design of signaling system testbench for highspeed signaling is described and developed software module are presented.

경부고속전철(KTX)의 운행은 서울동대구간은 고속선에 의한 고속 운행을 실행하는 반면, 동대구부산간은 기존선 전철화 및 선로 개량 사업을 통해 기존선을 운행한다. 그 결과 남서울, 북대전, 남대전, 및 북대구의 기존선과 고속선 연결부 인터페이스는 가장 중요한 검토 및 연구 대상으로, 기존선과 고속선 간의 속도 형상에 대한 호환성은 KTX 차량의 적절한 운행을 결정하는 기본 요소이며 또한 필수 요소로 작용한다. 따라서 본 연구에서는 기존선과 고속선 신호 시스템의 호환성에 따른 속도 천이를 분석한다.

Analysis of loading capacity of Korean HighSpeed Train by using MAS(Moving Autoblock System) methodA new block system  MAS (Moving Autoblock System) whose efficiency is higher than FAS(Fixed Autoblock System) in the loading capacity is required to accomodate the increasing transport volume. That MAS has higher efficiency has already been verified through various studies, especially in a line with different types of travelling trains. The efficiency of MAS for Korean high speed line with two different train model is analyzed by computer simulation. The results show that MAS is more efficient than FAS in the loading capacity.

본 논문은 Grafcet[1]을 이용하여 고속전철 승강문 제어를 실행하기 위한 운영 모드에 대해 논의한다. 고속전철에 사용하는 승강문 제어 관련 동작 상태의 정의 및 제어 조건[2]을 인용하여 승강문 제어를 위한 기본 사양 및 운영자 요구사양을 정의한 다음, 열차편성을 1개의 동력차와 4개의 객차로 가정한 후, 이에 대한 승강문 운영 모드 관련 순차 프로그램을 Grafcet 을 이용하여 구성하였다.

Currently KERI is participating a project whose goal is to develop the Korean HighSpeed Train(KHST) with maximum speed of 350kph. KERI's responsibility is the electrical system engineering that includes engineering design of an onboard computer system for diagnosis and control of train set and electrical/mechanical devices. A system engineering approach of the design is performed in order to guarantee the passenger safety and economically viable train for onboard control system construction, operation and maintenance. This paper presents the draft engineering des onboard computer system that ensures the s and reliability of KHST. The draft is focuse network interfaced distributed processing system.

It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheelrail adhesion characteristics. To study adhesion characteristic is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheelrail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory. In this paper, for improving adhesion performance shows actually control methods.

In this paper, for IGBT inverter of electric car studied new vibration test method. It made a partial amendment of the existing standard. Using new vibration test method is tested actually IGBT inverter. The result on vibration test for IGBT inverter shows an excellent performance.

High speed switching action of PWM inverter is being further advanced for electric motor vehicles. Due to this high speed switching action, extensive high frequency electromagnetic noise emerges. Therefore countermeasures against electromagnetic interference of electric motor vehicles become increasingly important. This paper describes the theory and countermeasure principle of EMI prevention and EMI test method for Korean Standard EMU.

본 논문에서는 철도 수요예측 문제의 유형을 목적에 따라 3가지로 분류하였고, 최근 철도자원을 재고관리 차원에서 접근하고자 하는 시각에 따라 분배모형으로써 적응필터를 사용하는 방법의 타당성에 대해 설명하였다. 또 철도 승객수요의 주요 특징을 분석하였으며, 철도 승객수요 예측의 요구사항 및 방법론을 대규모 재고관리 시스템의 일반적 요구사항에 따라 정리하였다. 영향인자에 대한 분석으로 요일별 계절변동 지수를 정량적으로 산정하였다. 적응필터를 이용한 철도 승객수요 예측의 예제를 제시하였으며, 예측에의 정확성에 대한 비교를 제시하였다.

The train system in a big city has the serious problem of the shortage of transport capacity. And because of the nowaday energy crisis, the research to reduce the energy consumption in the train system has been progressed. In this paper, it is expected that the train operation mixing slow trains and fast trains enable us to increase transport capacity and to reduce energy consumption. In this paper, the train operation mixing slew trains and fast trains is modelled and the change of energy consumption and transport capacity depending upon the operation formation is simulated.

The automatic/driverless operation which are great important techniques in metro railway are required to increase higher safety, greater reliability, and transport capacity. To satisfy such demands, we must have the system design and testing technique for the railway system operation. These techniques are related to the onboard train control and communication systems which include TCMS(Train Control and Monitoring System), ATO(Automatic train Operation), ATC(Automatic train Control), and TWC(Train to wayside communication). These subsystems must be interfacing with not only each others but also the signal system on the ground. We tested the train control system on the 7 line that has been developed on the basis of the standardized type EMU for korea railway systems.

This paper describes the method to develop the ATO software system. The software design is based on VxWorks, a Real Time Operating System. ATO calculates tractive effort/braking effort to keep the train at a certain speed reference at each moment. The speed reference is calculated by the ATO from a number of external factors. The ATO with this software is installed standardized EMU. and tested In Seoul Line 7.

The ATO(Automatic Train Operation System) system is equipment for automatic and driverless operation of electric train with minimum control of operator. In this paper, we made ATO system with national technic and passed type test. We are convinced of reliability and safety of the ATO system on the seoul metro 7 line.

So many terms of electrical engineering are nationalized words and Japanese words written in Chinese characters because electrical engineering is introduced from foreign countries. Many students who are not familiar to Chinese characters are difficult to study with this terms in the first step of electrical engineering. In this study, the systematic compilation method of electrical dictionaries is proposed, which is based on the method of the standard Korean dictionary. Through this method, more systematic Korean electrical dictionaries will be compiled.